Well, it keeps referring to sessions manager in what is reported in the error. Curious.
So we continue sluething ...
"How to check this php-fpm? fastcgi?"
One way it to see what's running apache wise:
ps aux |grep httpd
In Fedora think that's how the distro calls apache.
Is there a log for php-fpm in /var/logs?
Do you have mod_php extension loaded?
php -i |grep mod
How about:
php -i |grep php-fmp
Something that I install .. multitail ... allows me to monitor (see in realtime) logs I set up. Example:
In /usr/local/bin/ a script called multi
which has (your server may not have webmin installed nor the other mods for apache ... like evasive) - those are up to you.
multitail -i /var/log/httpd/ssl_access_log -i /var/log/httpd/ssl_error_log -i /var/log/httpd/access_log -i /var/log/httpd/error_log -i /var/log/webmin/miniserv.log -i /var/log/webmin/miniserv.error -i /var/log/webmin/webmin.log -i /var/log/secure -i /var/log/messages -i /var/log/httpd/mod_evasive
I can 'watch' all of those at once.
Since I don't run Fedora ... maybe this will help you:
https://docs.fedoraproject.org/en-US/quick-docs/getting-started-with-apache-http-server/
Also, RH family distro's typically install and run SeLinux - security enhanced linux. It has been known to need tweaking for a Moodle:
https://docs.fedoraproject.org/en-US/quick-docs/changing-selinux-states-and-modes/
Issue: sestatus as root
Is SeLinux 'enforcing'? Could be the reason for the issues you are seeing. Checking selinux logs will tell.
What I normally do ... set selinux to 'permissive' so I can see what it would have blocked or complain about, fixing those, then when no more complaints are logged, turn selinux to 'enforcing'.
Then monitoring site and apache logs/error logs/+selinux logs for any more complaints ... or errors.
'SoS', Ken