Title: Error code 521 Last modified: May 19, 2025 --- # Error code 521 * Resolved [marseem](https://wordpress.org/support/users/waseemsannib/) * (@waseemsannib) * [1 year, 9 months ago](https://wordpress.org/support/topic/error-code-521/) * Hello, * After connecting my website to Cloudflare and inserting the Nameservers and DNS I can’t access my website anymore. Is something from my side that should be implemented or it’s just from my host provider? Do I need to wait for 24 hours to check whether my website will come back or not? * Also, in DNS configuration in my host cpanel, there was a message: changes to settings will not be fully active until 24 hours after activation due to the decentralized structure of DNS. * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ferror-code-521%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 3 replies - 1 through 3 (of 3 total) * [Bhavik Panchal](https://wordpress.org/support/users/beaubhavik/) * (@beaubhavik) * [1 year, 9 months ago](https://wordpress.org/support/topic/error-code-521/#post-17964416) * [@waseemsannib](https://wordpress.org/support/users/waseemsannib/) Error code 521 indicates that Cloudflare is unable to establish a connection to your origin web server. This can occur for several reasons, particularly after changing your DNS settings to connect your website to Cloudflare. Here’s a breakdown of potential causes and solutions: Possible Causes of Error Code 521 - **Web Server Issues**: Your origin server might be down or not responding. Ensure that your web server is running properly and check its error logs for any issues. - **Firewall or Security Settings**: Your server’s firewall may be blocking Cloudflare’s IP addresses. Make sure that your firewall settings allow connections from Cloudflare IPs and are not set to block or rate limit them. - **Incorrect DNS Configuration**: If your DNS settings are not correctly configured, Cloudflare may not be able to reach your server. Double-check that the nameservers and DNS records are set up correctly in your hosting provider’s control panel. - **SSL Configuration**: If you are using HTTPS, ensure that your server is configured to accept connections on port 443. If necessary, consider switching to “Flexible” SSL in Cloudflare’s SSL/TLS settings, which can help if your origin server does not support SSL. * Steps to Resolve the Issue 1. **Check Server Status**: Verify that your web server is operational. You can do this by accessing it directly via its IP address. 2. **Review Firewall Settings**: Ensure that your firewall is not blocking Cloudflare’s IP addresses. You may need to whitelist these IPs. 3. **DNS Propagation**: As you mentioned, DNS changes can take up to 24 hours to propagate fully. If you have just made the changes, it may be worth waiting to see if the issue resolves itself. 4. **Contact Hosting Provider**: If you are unable to diagnose the problem, reach out to your hosting provider for assistance. They can check if there are any issues on their end that might be causing the connection failure. 5. **Test with Development Mode**: If you have access to Cloudflare, try enabling Development Mode temporarily. This can sometimes bypass caching and allow you to see if the site is accessible without Cloudflare’s interference. * Conclusion * In summary, the error code 521 is likely due to connectivity issues between Cloudflare and your origin server, which could stem from server downtime, firewall settings, or DNS misconfigurations. It is advisable to check your server’s status, review your firewall settings, and possibly wait for DNS propagation. If the issue persists, contacting your hosting provider for further assistance is recommended. * Citations: [1] [https://wordpress.org/support/topic/error-code-521/](https://wordpress.org/support/topic/error-code-521/)[ 2] [https://community.cloudflare.com/t/error-code-521/418286](https://community.cloudflare.com/t/error-code-521/418286)[ 3] [https://community.cloudflare.com/t/community-tip-fixing-error-521-web-server-is-down/42461](https://community.cloudflare.com/t/community-tip-fixing-error-521-web-server-is-down/42461)[ 4] [https://community.cloudflare.com/t/getting-http-521-randomly-on-my-website-with-the-proxy-option/627172](https://community.cloudflare.com/t/getting-http-521-randomly-on-my-website-with-the-proxy-option/627172) * Thread Starter [marseem](https://wordpress.org/support/users/waseemsannib/) * (@waseemsannib) * [1 year, 9 months ago](https://wordpress.org/support/topic/error-code-521/#post-17964501) * Thank you for your reply and recommendations. I’m sure that my setup is correct. I just need to ask, why sometimes my website open as in the screenshot but once I click on anything I get the same 521 error? Also you can see the DNS configuration is inactive because maybe as you mentioned for the DNS propagation waiting. * My host provider replied to me with this message: * I see that you have tried to set up a name server (NS) for your domain several times today. The purpose of this record is to forward your DNS requests to another name server. * After you have set it up, you must wait 24 hours for it to be fully processed, which is why you receive the message that the host is not yet connected. * Once a name server (NS) has been set up, you will no longer be able to use the other records. That is why you see the message that the other records are inactive. * So, do you think it’s just waiting for the DNS to be connected and everything should work as expected? * Thank you again for your support * [https://ibb.co/gZ0N1m8](https://ibb.co/gZ0N1m8) * [https://ibb.co/JFQftxZ](https://ibb.co/JFQftxZ) [https://ibb.co/L6FDcDP](https://ibb.co/L6FDcDP) [https://ibb.co/gZ0N1m8](https://ibb.co/gZ0N1m8) * Moderator [Support Moderator](https://wordpress.org/support/users/moderator/) * (@moderator) * [1 year, 9 months ago](https://wordpress.org/support/topic/error-code-521/#post-17967847) * Thread continues at [https://wordpress.org/support/topic/521-error-website-server-is-down/](https://wordpress.org/support/topic/521-error-website-server-is-down/) Viewing 3 replies - 1 through 3 (of 3 total) The topic ‘Error code 521’ is closed to new replies. ## Tags * [firewall](https://wordpress.org/support/topic-tag/firewall/) * [server](https://wordpress.org/support/topic-tag/server/) * [SSL](https://wordpress.org/support/topic-tag/ssl/) * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/) * 3 replies * 2 participants * Last reply from: [Support Moderator](https://wordpress.org/support/users/moderator/) * Last activity: [1 year, 9 months ago](https://wordpress.org/support/topic/error-code-521/#post-17967847) * Status: resolved ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics