Getting HTTP 521 randomly on my website with the proxy option

Website, Application, Performance
3

Hello Daniel,

It seems like you’re experiencing intermittent HTTP 521 errors, which indicate that Cloudflare is unable to establish a connection to your server. Here are some steps to troubleshoot the issue:

  1. Check your server’s firewall settings to ensure that it’s not blocking Cloudflare’s IP ranges. You can find the list of Cloudflare IP ranges here.
  2. Ensure that your web server (Apache, Nginx, IIS, etc.) is running and there are no issues with the service.
  3. Verify that there are no network issues on your server’s end that could be disrupting the connection.
  4. If you’re using an SSL certificate, make sure it’s valid and properly configured on your server.
  5. Review Cloudflare’s Community Tip for Error 521 for additional troubleshooting steps.
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