Error 522 Connection Timed Out Plus 15 CDN Issues Fix Tips

So, the first question is; what happens if get an Error 522 Connection Timed Out if you are using Cloudflare as your preferrable Content Delivery Network (CDN) carrier for your site? Well, it usually means that the initial connection between Cloudflare’s network and the origin web server timed out. And then, as a result, the web page can not be displayed.

The next question is; what can I do to resolve or fix this Error 522? Well, in this article, we’re going to learn about all that in detail, together. We’ll look into all scenario cases that lead to a Connection Timed Out Error 522 for any given website. In this case, while referring to Cloudflare CDN as our main guideline. Plus all the possible solutions to this.

Overview: Globally, Cloudflare Content Delivery Network provides all its key users with very unique overall website performance optimization capabilities. Whereby, they cache static content, accelerate dynamic content, and make it easy to optimize outbound content. In this PDF guideline, you’ll learn that it goes beyond just a traditional CDN.

Why A Content Delivery Network (CDN) Matters

Before we learn more about what Error 522 Connection Timed Out is and the best solutions for the same, it’s good to know the role of a CDN in all this. Basically, a CDN like Cloudflare makes websites run faster, and having a fast site is an important part of visitor satisfaction. Site speed is crucial to providing a positive experience for website visitors.

Because, obviously, slow load times result in higher bounce rates, shorter time spent on the site, and lower conversion rates. To put it simply, latency hurts your bottom line. In February of 2012, the multinational retailer Walmart conducted an analysis (white paper) to understand how website page performance affects e-commerce conversion rates.

The white paper covers:
  • Global distributed network
  • Static content caching
  • Custom caching management
  • Edge side code
  • study (Feb 2012)
  • Dynamic content acceleration
  • Front-end optimization and client intelligence
  • Reporting

Specifically, the study focused on the official website of Walmart ( for its own e-commerce store. The webstore did $7.7 billion in sales, hit billions of page requests, and hosted millions of active product SKUs in 2012. Overall, this study revealed a shocking relationship between page load times and conversion rates.


Cloudflare’s performance features dramatically improve load times for users accessing your static and dynamic web content. This increases customer satisfaction and potentially drives conversion rates up. Because Cloudflare CDN reduces hops and lowers latency, a request on Cloudflare’s network takes less than 23 milliseconds to serve on average.

What Error 522 Connection Timed Out Is All About

Technically, Error 522 Connection Timed Out indicates that Cloudflare is unable to reach the origin web server, and the request times out. In other words, an Error 522 means that the request was able to connect to your web server, but that the request didn’t finish. The most likely cause is that something on your server is hogging resources.

On one side, if you’re a visitor of the website indicating this error: Cloudflare will request you to ‘Please try again in a few minutes.‘ And then, after refreshing the page, you’ll see the results normalize for you to continue browsing. But, if at all nothing happens, you can always revisit the site page after some time as you allow the owners to resolve the causes.

Related Topic: 5xx Server Errors | How To Fix Them In A Simple Steps Guide

You should note that Cloudflare Support only assists the domain owner to resolve issues. Meaning, that if you are a site visitor, you can report the problem to the site owner and inform them about this error. On the other side, if you’re the owner of this website: you’ll need to follow some few, or rather, additional troubleshooting information by Cloudflare.

Rather than just refreshing the particular website page — that’s if the error is consistent. Usually, in this case, you’ll need to contact your hosting provider letting them know your web server is not completing requests. Not forgetting, there are some requirements of the error details that you’ll also need to provide your hosting provider with.

Consider the following:
  1. Specific Error 522 Connection Timed Out and message
  2. The occurrence time and timezone of the Error 522 Connection Timed Out
  3. Specifically, the site URL page that resulted in the HTTP 5XX error

That said, additional details to provide to your hosting provider or site administrator are listed within each error as we’ll see in the description below. Also, bear in mind, that the Cloudflare Custom Error Pages do change the appearance of default error pages discussed below too.

NB: Dedicated email support is available for all Pro, Business, and Enterprise Plan users. Business and Enterprise plan users also have access to chat support (explore Cloudflare plans).

The Main Error 522 Connection Timed Out Causes Plus Other Issues 

As we mentioned earlier, the error 522 connection timed out message is a server-side issue common for websites using Cloudflare. In order to troubleshoot and fix this error issue, make sure you have access as a server administrator. Since it’s a server error as the only other option is to contact the website’s owner.

According to Hostinger, The Error 522 connection timed out message is an HTTP status code. A content delivery network (CDN) service, like Cloudflare, speeds up the network connection between a browser user and a website’s origin server. However, sometimes the server fails to respond within a specified time.

This issue also means that the Transmission Control Protocol (TCP) handshake between the web server and Cloudflare has failed. The TCP handshake is essential to establish a connection whenever this CDN receives a user request.

Below are some of the most common reasons behind connection timeouts:
  • Server Overload: When an origin server faces too many requests, it cannot respond in time.
  • A Firewall Flags/Blocks CDN Requests: Some web hosting providers’ firewall features might block Cloudflare IPs.
  • Incorrect IP Address: The addresses on your domain name system (DNS) do not match with the ones on Cloudflare.
  • Disabled KeepAlive: Cloudflare activates KeepAlive messages by default. And if disabled, the connection setup fails.

Any of these cases can result in error 522 on your website. Most browsers will show the same image and message. Whilst, indicating that the problem lies with the web host as shown in the sample illustration image below:

What Error 522 Connection Timed Out Is On A Cloudflare CDN

Important to realize, that the error cause is not always found in the origin server error logs. Therefore, you should check logs of all load balancers, caches, proxies, or firewalls between Cloudflare and the origin web server. Eventually, checking that the origin web server is active and accepting HTTP requests is the first step in troubleshooting Error 522.

Verify that the DNS settings in your Cloudflare account are correct. Error Analytics per domain are available within the support portal for your account.  Such Error Analytics allows insight into the overall HTTP error codes. Then, it provides the URLs, responses, origin server IP addresses, and Cloudflare data centers needed to diagnose and resolve it.

To View Error Analytics:
  • Firstly, navigate to the Cloudflare support portal.
  • Secondly, refer to instructions about filing a support ticket to learn how to reach the support portal.
  • Thirdly, scroll down to the Error Analytics section.
  • Thereafter, click Visit Error Analytics.
  • And then, enter the domain to investigate.
  • A graph of Errors over time is displayed.
  • Click on a status code in the table beneath the graph to expand traffic error details.

Pro Note: This error is not caused by any Cloudflare malfunctions. Furthermore, this issue can happen no matter if you use a premium or a free version. Notably, Error Analytics is based on a 1% traffic sample. That said, in this article, you’ll learn more about how to fix the error 522 connection timed out error issues or see more details in the video below:

And now that you know, or have an idea of how to go about it, in addition to error 522 connection timed out, below are other more related error issues you should know about. As well as the key solutions to fix them.

1. Error 500 Error: There Is An Internal Server Issue

Generally, Error 500 indicates an issue with your origin web server.  Error establishing database connection is a common HTTP 500 error message generated by your origin web server.  Contact your hosting provider to resolve.


Provide details to your hosting provider to assist in troubleshooting the issue. However, if the 500 error contains “Cloudflare” or “Cloudflare-Nginx” in the HTML response body, provide Cloudflare support with the required information.

Consider the following:
  1. Your domain name
  2. The time and timezone of the 500 error occurrence
  3. The output of from the browser where the 500 error was observed (replace with your actual domain and hostname)

If you observe blank or white pages when visiting your website, confirm whether the issue occurs when temporarily pausing Cloudflare and contact your hosting provider for assistance.

2. Error 502 Error: Bad Gateway Or 504 Gateway Timeout

An HTTP 502 or 504 error occurs when Cloudflare is unable to establish contact with your origin web server.

There are two possible causes:
  • one; 502/504 from your origin web server (the most common cause)
  • two; 502/504 from Cloudflare

3. 502/504 Error: Originating From Your Origin Web Server

Cloudflare returns a Cloudflare-branded HTTP 502 or 504 error when your origin web server responds with a standard HTTP 502 bad gateway or 504 gateway timeout error.


Oftentimes, contact your hosting provider to troubleshoot these common causes at your origin web server:

  • Ensure the origin server responds to requests for the hostname and domain,
  • more so, within the visitor’s URL that generated the 502 or 504 error.
  • Investigate excessive server loads, crashes, or network failures.
  • Identify applications or services that timed out or were blocked.

4. 502/504 Error: The One Originating From Cloudflare

In reality, a 502 or 504 error originating from Cloudflare appears on your browser screen as follows. If the error does not mention “Cloudflare,” contact your hosting provider for assistance on 502/504 errors from your origin:

Example of an unbranded error 502 or 504 error originating from Cloudflare


To avoid delays in processing your inquiry, provide these required details to Cloudflare Support for fixing:

  1. The time and timezone the issue occurred.
  2. URL that resulted in the HTTP 502 or 504 response
    • (for example )
  3. Output from browsing to
    • (replace with the HTTP 502 or 504 error source domain and hostname)

5. Error 503: The Service Is Temporarily Unavailable

HTTP error 503 occurs when your origin web server is overloaded with two possible causes discernible by the error message:

  • The error doesn’t contain “Cloudflare” or “Cloudflare-Nginx” in the HTML response body.

Contact your hosting provider to verify if the rate limit requests to your origin web server.

  • The error contains “Cloudflare” or “Cloudflare-Nginx” in the HTML response body.

A connectivity issue occurred in a Cloudflare data center. Provide Cloudflare support with this information:

  1. Your domain name
  2. The time and timezone of the 503 error occurrence
  3. The output of from the browser where the 503 error was observed
    • (replace with your actual domain and hostname)

6. Error 520: A Webserver Returns An Unknown Error

Error 520 occurs when the origin server returns an empty, unknown, or unexpected response to Cloudflare. A quick workaround while further investigating 520 errors is to either make the record DNS-only in the Cloudflare DNS app or temporarily pause Cloudflare.


Equally important, just like before, you should contact your hosting provider or site administrator and request a review of your origin web server error logs for crashes. As well as check for the common causes.

Such causes include:
  • Origin web server application crashes
  • Cloudflare IPs are not allowed at your origin
  • Headers exceeding 16 KB (typically due to too many cookies)
  • An empty response from the origin web server that lacks an HTTP status code or response body
  • Missing response headers or origin web server not returning proper HTTP error responses.
    • upstream prematurely closed connection while reading response header from upstream is a very common error to notice in logs. It indicates the origin web server was having issues which led Cloudflare to generate 520 errors.

Keep in mind, that 520 errors are prevalent with certain PHP applications that crash the origin web server. Whilst, bearing in mind, if 520 errors continue after contacting your hosting provider or site administrator, you’ll need to provide all the useful information to Cloudflare Support.

Consider the following:
  • Full URL(s) of the resource requested when the error occurred
  • Two HAR files:
    • one with Cloudflare enabled on your website, and
    • the other with Cloudflare temporarily disabled.
  • Output from 
    • (replace with your 520 error occurrence hostname and domain)
  • Cloudflare cf-ray from the 520 error message

7. Error 521: The Web Server Is Down

Error 521 occurs when the origin web server refuses connections from Cloudflare. Security solutions at your origin may block legitimate connections from certain Cloudflare IP Addresses. The two most common error causes are:

  • Offlined origin web server application
  • Blocked Cloudflare requests

Contact your site administrator or hosting provider to eliminate these common causes:

  • Ensure your origin web server is responsive
  • Review origin web server error logs to identify web server application crashes or outages.
  • Confirm Cloudflare IP addresses are not blocked or rate limited
  • Allow all Cloudflare IP ranges in your origin web server’s firewall or other security software
  • Confirm that — if you have your SSL/TLS mode set to Full or Full (Strict) — you have installed a Cloudflare Origin Certificate. Or even find additional troubleshooting information on the Cloudflare Community.

8. Error 522: Connection Timed Out

Error 522 occurs when Cloudflare times out contacting the origin web server. Two different timeouts cause HTTP error 522 depending on when they occur between Cloudflare and the origin web server:

  1. Before a connection is established, the origin web server does not return an SYN+ACK to Cloudflare within 15 seconds of Cloudflare sending an SYN.
  2. After a connection is established, the origin web server doesn’t acknowledge (ACK) Cloudflare’s resource request within 90 seconds.

An HTTP 524 error occurs if the origin web server acknowledges (ACK) the resource request after the connection has been established, but does not send a timely response.


Contact your web hosting provider to check the following common causes at your origin web server:

  • (Most common cause) Cloudflare IPs are rate limited or blocked in .htaccess, iptables, or firewalls. Confirm your hosting provider allows Cloudflare IP addresses.
  • An overloaded or offline origin web server drops incoming requests.
  • Keepalives are disabled at the origin web server.
  • The origin IP address in your Cloudflare DNS app does not match the IP address currently provisioned to your origin web server by your hosting provider.
  • Packets were dropped at your origin web server.

If you are using Cloudflare Pages, verify that you have a custom domain set up and that your CNAME record is pointed to your custom Pages domain. Fortunately, all the instructions on how to set up a custom Pages domain can be found here.

In the same fashion, if none of the above leads to a resolution, request the following information from your hosting provider. Or rather, your site administrator before contacting Cloudflare support.

Consider the following:
  • On one hand, an MTR or traceroute from your origin webserver to a Cloudflare IP address that was most commonly connected to your origin web server before the issue occurred.
  • Identify a connecting Cloudflare IP recorded in the origin web server logs.
  • On the other hand, details from the hosting provider’s investigation such as pertinent logs or conversations with the hosting provider.

9. Error 523: The Origin Is Unreachable

The enumerate, Error 523 occurs when Cloudflare cannot contact your origin web server. Typically, this occurs when a network device between Cloudflare and the origin web server doesn’t have a route to the origin’s IP address.


Contact your hosting provider to exclude the following common causes at your origin web server:

  • Confirm the correct origin IP address is listed for A or AAAA records within your Cloudflare DNS app.
  • Troubleshoot Internet routing issues between your origin and Cloudflare, or with the origin itself.

At all costs, if your hosting provider frequently changes your origin web server’s IP address, refer to Cloudflare’s documentation on dynamic DNS updates. However, if none of the above leads to a resolution, request the following information from your web hosting provider or site administrator:

  • An MTR or traceroute from your origin web server to a Cloudflare IP address that was most commonly connected to your origin web server before the issue occurred.
  • Identify a connecting Cloudflare IP from the logs of the origin web server.
  • If you manage your Railgun installation, provide the following:
    • A traceroute to your origin web server from your Railgun server.
    • The most recent Syslog file from your Railgun server.
  • Equally, if you use Railgun via a Cloudflare Hosting Partner, contact your hosting provider to troubleshoot the 523 errors.

10. Error 524: A Timeout Occurred

For your information, Error 524 indicates that Cloudflare successfully connected to the origin web server. But, the origin server did not provide an HTTP response before the default 100-second connection timed out.

In general, this can happen if the origin server is simply taking too long because it has too much work to do – e.g. a large data query, or because the server is struggling for resources and cannot return any data in time.


Here are the options we’d suggest to work around this issue:

  • Implement status polling of large HTTP processes to avoid hitting this error.
  • Contact your hosting provider to exclude the following common causes at your origin web server:
    • A long-running process on the origin web server.
    • An overloaded origin web server.

In nutshell, logging request response time at your origin web server helps identify the cause of resource slowness. Contact your hosting provider or even website administrator for assistance in adjusting log formats or search for related logging documentation for your brand of a web server such as Apache or Nginx.

  • Enterprise customers can increase the 524 timeouts up to 6000 seconds using the proxy_read_timeout API endpoint.
  • On one side, if you regularly run HTTP requests that take over 100 seconds to complete (for example large data exports), move those processes behind a subdomain not proxied (grey clouded) in the Cloudflare DNS app.
  • On the other side, if error 524 occurs for a domain using Cloudflare Railgun, ensure the lan.timeout is set higher than the default of 30 seconds and restart the railgun service.

11. Error 525: SSL Handshake Failed

525 errors indicate that the SSL handshake between Cloudflare and the origin web server failed. Error 525 occurs when these two conditions are true:

  1. The SSL handshake fails between Cloudflare and the origin web server, and
  2. Full or Full (Strict) SSL is set in the Overview tab of your Cloudflare SSL/TLS app.

Contact your hosting provider to exclude the following common causes at your origin web server:

  • No valid SSL certificate installed
  • Port 443 (or another custom secure port) is not open
  • No SNI support
  • The cipher suites accepted by Cloudflare do not match the cipher suites supported by the origin web server

If 525 errors occur intermittently, review the origin web server error logs to determine the cause. Configure Apache to log mod_ssl errors. Also, Nginx includes SSL errors in its standard error log, but may possibly require an increased log level.

Additional checks:
  • Check if you have a certificate installed on your origin server. You can check this article for more details on how to run some tests. In case you don’t have any certificate, you can create and install our free Cloudflare Origin CA Certificate.

NB: Using the Origin CA certificates allows you to encrypt traffic between Cloudflare and your origin web server.

  • Review the cipher suites your server is using to ensure they match what is supported by Cloudflare.
  • Check your server’s error logs from the timestamps you see 525s to ensure there are errors that could be causing the connection to be reset during the SSL handshake.

12. Error 526: An Invalid SSL Certificate

Error 526 occurs when these two conditions are true:

  1. Cloudflare cannot validate the SSL certificate at your origin web server, and
  2. Full SSL (Strict) SSL is set in the Overview tab of your Cloudflare SSL/TLS app.

Eventually, for a potential quick fix, set SSL to Full instead of Full (strict) in the Overview tab of your Cloudflare SSL/TLS app for the domain. Additionally, you can request your server administrator or hosting provider to review the origin web server’s SSL certificates and verify that:

  • First of all, the certificate is not expired or the certificate is not revoked
  • Second, the certificate is signed by a Certificate Authority (not self-signed)
  • The requested or target domain and hostname are in the certificate’s Common Name or Subject Alternative Name
  • Thirdly, your origin web server accepts connections over port SSL port 443
  • Temporarily pause Cloudflare and visit
  • Replace with your hostname and domain) to verify no issues exist with the origin SSL certificate.

Screen showing an SSL certificate with no errors

If the origin server uses a self-signed certificate, configure the domain to use Full SSL instead of Full SSL (Strict). Perse, refer to recommended SSL settings for your origin. In fact, if all goes well, it will look something like the image above.

13. 527 Error: Railgun Listener To Origin Error

A 527 error indicates an interrupted connection between Cloudflare and your origin’s Railgun server (rg-listener).

Common causes include:
  • Firewall interference
  • Network incidents or packet loss between the Railgun server and Cloudflare

For additional details to aid troubleshooting, increase Railgun logging. Below are other error 527 common causes:

  • Connection timeouts
  • LAN timeout exceeded
  • Connection refusals
  • TLS/SSL related errors

If contacting Cloudflare support, provide the following information from the Railgun Listener:

  • The full content of the railgun.conf file
  • The full content of the railgun-nat.conf file
  • Railgun log files that detail the observed errors

14. TLS/SSL Related Errors And Error 530

In most cases, the following errors appear in the Railgun logs if TLS connections fail:

connection failed remote error: handshake failure
connection failed dial tcp refused
connection failed x509: certificate is valid for, not

Uniquely, if TLS/SSL errors occur, check the following on the origin web server and ensure that:

  • Port 443 is open
  • An SSL certificate is presented by the origin web server
  • the SAN or Common Name of the origin web server’s SSL certificate contains the requested or target hostname
  • SSL is set to Full or Full (Strict) in the Overview tab of the Cloudflare SSL/TLS app

By all means, if your origin web server SSL certificate is self-signed, set validate.cert=0 in railgun.conf.

Lastly, HTTP error 530 is returned with an accompanying 1XXX error displayed. Search for the specific 1XXX error within the Cloudflare Help Center for troubleshooting information.

15. 527 Railgun Listener To Origin Error Types

Realistically, in relation to Error 522 Connection Timed Out is 527 Railgun Listener To Origin Error. It’s an error that indicates that the connection between Cloudflare and the origin’s Railgun server (rg-listener) was interrupted. This could result from a firewall block or other network incident between rg-listener and Cloudflare.

Such as packet loss on the line. The LAN Timeout Exceeded is one of the issues that fall under 527 Railgun Listener To Origin Error types. Others are Connection Timeouts & Connection Refusals. Whereby, it’s generated if the origin web server does not send an HTTP response to the Railgun Listener within the 30-second default timeout:

  connection failed dial tcp i/o timeout

The time is adjusted by the lan.timeout parameter of the railgun.conf file.


Either increase the lan.timeout limit in railgun.conf or review the webserver configuration. Contact your hosting provider to confirm if the origin web server is overloaded.

Connection Timeouts & Connection Refusals

On one hand, the Connection Timeouts is another Railgun Log Error that indicates a connection failure between the Railgun Listener and your origin web server:

connection failed dial tcp i/o timeout
no response from origin (timeout)

Contact your hosting provider for assistance to test for connectivity issues between your origin web server and your Railgun Listener. For example, a netcat command tests connectivity when run from the Railgun Listener to the origin web server’s SERVERIP and PORT (80 for HTTP or 443 for HTTPS):


On the other hand, the Connection Refusals Error types appear in the Railgun logs when requests from the Railgun Listener are refused:

Error getting page: dial tcp refused

Allow the IP of your Railgun Listener at your origin web server’s firewall.

Takeaway Notes:

In general, the public Internet does its best to deliver your content — but it can’t account for network congestion. Leading to slow load times and a degraded end-user experience. The Cloudflare network is different. It routes over 10 trillion global requests per month. One thing is for sure, Cloudflare was created to ease all these difficulties.

As well as to empower users with the resources to make their sites, apps, and blogs safe and performant. So, if you’re a pro web developer, you can start straight away! You can do all this through the use of a powerful edge network that provides content and other services as close to you as possible. Meaning, that you’ll get the information quite fast.

Learn More: Why Cloudflare Is The Best For Web Performance & Security

Nowadays, most people use Cloudflare services for the purposes of increasing the security and performance of their websites and services. It’s on a mission to help build a better Internet. Now that it’s one of the biggest networks operating on the Internet. It powers Internet requests for ~15% of the Fortune 1k for more than 1 billion unique IP addresses daily.

Today, businesses, non-profits, bloggers, and anyone with an Internet presence boast faster, more secure websites and apps thanks to Cloudflare. Now that it’s one of the world’s largest networks. More than 25 million Internet properties are on its platform, and its network is growing by tens of thousands per day.

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One way to make your site run smoothly is for you to use caching tools to purge the site cache and clear any unnecessary files. Not forgetting, Error 522 Connection Timed Out is a very common issue with many sites including our own. That’s why our Web Tech Experts highly recommend that you always clean your website house.

More so, to make it friendly to both users and CDNs. For instance, if you make an edit to one of your posts and find that you can’t see the changes immediately but want them to be available, that would be a good reason to purge the cache manually. Most caching plugins are set up to purge the cache after a certain amount of time.

Learn More: What Is Caching? The Main Benefits Plus How To Purge Cache

Like once a day or once every few hours, or may even once a week. But, if you’ll need more help, you can always Consult Us and let us know how we can sort you out. Likewise, feel free to share your overall site experience while using a CD or not. You can also share your additional opinions, thoughts, suggestions, recommendations, contributions, etc.

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