Not all hosting providers setup servers the same. Panels are different (cPanel/Directadmin/Webmin/Plesk) as well as how the engineers of hosting have set things up for their customers.
Case in point ... some systems setup PHP to log errors to an error_log file in the directory where the error occurs. So to find where the errors are occuring, best to have command line access and from the moodle code directory, issue the following command:
find ./ -name error_log
That will kick out a listing/location of those error_log files.
Since you have Plesk, best to use its docs .... for many things.
https://docs.plesk.com/en-US/obsidian/quick-start-guide/plesk-tutorial.74376/
Do you have a Terminal icon for a shell? Suggest learning some command line for there are some hidden stuff not shown in the GUI ... another example: the superuser for your DB server (typically root). You won't see the password for the superuser ... not in any DB tool nor in PHPMyAdmin ... but it's there ... if you know/discover where to look. Reason hidden ... support issues ... techs from hosting don't keep a sheet of customers DB superusers passwords but if they are ever called on by you to assist with a DB problem, they would need superuser creds!
You don't have to be a command line ninja ... just enough (je) to get the job done. And, it's a big plus to learn 'je' cause there are some command line only php scripts in moodle code ... the one most often used in code/admin/cli/
Reference:
https://docs.moodle.org/405/en/Administration_via_command_line
Another case in point ... GUI software to do a site backup. IMHO, best to do moodle site backups via command line cause EVERY linux distro has tar (tape archive tool which can create backup files) and if running MySQL or MariaDB, mysqldump for making a backup of the DB for moodle.
https://docs.moodle.org/405/en/Site_backup
The GUI tool you were using presents a nice table parsed from log files which are ascii (txt) and those log files might contain more than the GUI is programmed to see.
Suggest command line viewing of those logs!
Also web server logs can be customized ... many providers do minimal.
Your Journey begins!
'SoS', Ken