I'm configuring a MediaWiki install and running into a few problems, 500 errors.
In a few cases I was able to get the error message to appear on screen, but having php error logs would be ideal.
I turned on error logging in the PHP Settings Plesk screen with no success. Log files aren't being recorded anywhere that I can see. I've also tried combinations of telling it to show all errors & notices, just errors, to display errors on screen and in logs, and only in logs. Still no logs.
Error logs like the ones your describing are a function of an Apache server, so it wouldn't be available on a Plesk hosting plan that uses IIS.
You can enable detailed errors in Plesk hosting plans by updating your web.config file per the following instructions. https://uk.godaddy.com/help/get-detailed-errors-16085 ^M