Apache is failing to start on a Plesk server: "Cannot load /usr/lib/apache2/modules/libphp7.4.so into server"

Symptoms

• The Apache web server is failing to start on a Plesk server
• Last lines from CLI command journalctl -xeu apache2 are:

Aug 31 10:09:44 server systemd[1]: Starting The Apache HTTP Server…
Aug 31 10:09:44 server apachectl[953]: apache2: Syntax error on line 146 of /etc/apache2/apache2.conf: Syntax error on line 3 of /etc/apache2/mods-enabled/php7.4.load: Cannot load /usr/lib/apache2/modules/libphp7.4.so into server: /usr/lib/apache2/modules/libphp7.4.so: cannot open shared object file: No such file or directory
Aug 31 10:09:44 server apachectl[920]: Action 'start' failed.
Aug 31 10:09:44 server apachectl[920]: The Apache error log may have more information.
Aug 31 10:09:44 server systemd[1]: apache2.service: Control process exited, code=exited, status=1/FAILURE
Aug 31 10:09:44 serverr systemd[1]: apache2.service: Failed with result 'exit-code'.
Aug 31 10:09:44 server systemd[1]: Failed to start The Apache HTTP Server.

Cause

Apache is trying to load PHP 7.4 provided by OS vendor which is not installed on the server.

Resolution

Move the following files:

# mv /etc/apache2/mods-enabled/php7.2.load /root/php7.4.load

# mv /etc/apache2/mods-enabled/php7.4.conf /root/php7.4.conf

Restart the Apache service:

# systemctl restart apache2.service