Failed to Make Connection to Backend: httpd-UDS

Symptoms

When loading a domain within a browser, you may receive the following error: 

Service Unavailable

The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Additionally, a 503 Service Unavailable error was encountered while trying to use an ErrorDocument to handle the request.

Upon checking the apache error log, the following error is appended: 

[$(date)] [proxy_fcgi:error] [pid 8094] [client 73.136.136.178:58140] AH01079: failed to make connection to backend: httpd-UDS, referer: http://yoursimplyhired.com/wp-admin/
[Fri Jun 26 23:32:06.591238 2020] [proxy:error] [pid 8094] (13)Permission denied: AH02454: FCGI: attempt to connect to Unix domain socket /opt/cpanel/ea-php72/root/usr/var/run/php-fpm/a1ba87f4b576cd4f8722c78753deae434bb9b122.sock (*) failed

Description 

This can be caused when there is a communication error between PHP-FPM and apache, resulting in apache being unable to serve the request. 

Workaround

Pass a restart to the apache_php_fpm service using the following script: 

/scripts/restartsrv_apache_php_fpm