Site does not work on PHP-FPM on Plesk: 503 service unavailable

[Suhitha]

Question: Site does not work on PHP-FPM on Plesk: 503 service unavailable


Applicable to:

• Plesk for Linux

Symptoms

• Sites that use the same PHP-FPM version (for example, 7.2 are not working):

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503 service unavailable

• The following error appears in the domain's error log /var/www/vhosts/system/example.com/logs/error_log:

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[proxy_fcgi:error] [pid 15605:tid 140353550149376] [client 203.0.113.2:45388] AH01079: failed to make connection to backend: httpd-UDS
[proxy:error] [pid 15605:tid 140353373902592] (2)No such file or directory: AH02454: FCGI: attempt to connect to Unix domain socket /var/www/vhosts/system/example.com/php-fpm.sock (*) failed

• Socket /var/www/vhosts/system/example.com/php-fpm.sock does not exist and switching PHP handler to another one at Plesk > Domains > example.com > PHP Settings recreates it, but switching PHP handler back removes it again

• Running the plesk repair web -n command provides output that is similar to the following:

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Checking for obsolete PHP-FPM configuration files
Domain example.com ............................................. [ERROR]
- Domain example.com with PHP handler plesk-php82-fpm has
obsolete PHP-FPM configuration file
/opt/plesk/php/8.1/etc/php-fpm.d/example.com

Cause

The php-fpm.sock files for several domains are missing, because the PHP-related configuration files for the affected domains and PHP versions have either become corrupted or have gone missing entirely.


Resolution

1.Log into the server via SSH

2.Restart all PHP-FPM services that are assigned to domains by executing the following command:

# systemctl restart plesk-php*

3.Recreate the missing or corrupted configuration files and PHP sockets for all domains by executing the following command:

# plesk repair web -y