I am facing Error 521 for one of my website. I have Cloudflare installed in my other webiste applications on Linode server which are working. Cloudflare version is 3.4.1 in all the applications.
Initial fixers I tried are as follows:-
Ensure your origin web server is responsive - Yes it is responsive.
Review origin web server error logs to identify web server application crashes or outages. - It is showing php-fpm segmentation fault. I restarted php-fpm but it didnot fix the issue.
Confirm [Cloudflare IP addresses] are not blocked or rate limited - None of the IPS are blocked.
Whitelist all Cloudflare IP ranges in your origin web server’s firewall or other security software
Also I reviewed the additional steps to rectify this but unfortunately couldn’t get it working.
Can somebody give some insight on how to debug this further or fix it permanently. Also let me know if any configuration issues might cause this problem.
That is very non-Cloudflare related. php-fpm segfaulting if very bad and indicates an issue with the server’s installation of php and/or an old/bad linux install. I’d recommend contacting your host about this, or if you’re on IaaS (digitalocean, aws, gcp, etc), recreating your VPS from scratch.
The host provider is Linode and they said there are no issues from there end. Also I have many applications running on my Linode machine which are working fine except for this one. If I uninstall cloudflare extension my web application works fine.
The host provider is Linode and they said there are no issues from there end. Also I have many applications running on my Linode machine which are working fine except for this one. If I uninstall cloudflare extension my web application works fine.
