how to remove server error

when there is any kind of issues related to it server then enable the detection problem, window troubleshooting and also reset your window.then after you face issues related to it, you can contact the service host provider which solve the issue related to it.

I think you are talking about 500 - Internal server error.
This is the most common HTTPs error code. This means you do not have the problem with your browser or internet connection but with the web server.
To solve this error you need to do following things:

Reload the web page
Delete your browser's cookies
Check .htaccess file and Creating a New .htaccess File
Check php memory limit
Clear your browser's cache
Contact your hosting provider if the issue is on the server that powers your site

Try to check /var/log/nginx/error.log if exist, if not, remove the line where you are assigning a diferent log file so he uses the standard one at /var/log/nginx/error.log

Also the socket thing is a recommendation and some people can recommend you to use tcp, but still should not be related to your error if you phpinfo.php is working.