Solution from technical support Plesk:
psa-mod-fcgid-configurator must be at least version libapache2-mod-fcgid-psa_2.3.9.4 (If less - you need to install a patch or update the system)
1. Switch the Apache mode from "mpm_event" to "mpm_prefork" in Pelsk> Tools and Settings> Apache Web server...
Debian 8.8 Plesk Onyx 17.8.2
Apache stops at night without any intervention (23/07/2017)
I assume that this happens after the automatic installation of Plesk updates
I'm not a very experienced user and if Apache sends a non-existent domain to some folder outside of domains, then I probably expect the response code to be 404. Moreover, the developers of Plesk have placed their page in this folder. Why not immediately set up and return the 404 response? This...
But when, when accessing any non-existing (arbitrary character set) subdomain, the code 200 is returned - this subdomain falls into the database of the search engines as existing. This is fundamentally not true.
The above problem occurred precisely because non-existent subdomains are sent to Plesk in a folder var/www/vhosts/default/htdocs
I deleted it and after a few days (not immediately for some reason) the server stopped working.
I believe that by default, something that does not exist should not...
Thank you. It all seems to have worked
Admin Plesk: nginx - Enabled
consol: /usr/local/psa/admin/sbin/nginxmng -s - Disabled
/usr/local/psa/admin/sbin/nginxmng -e - OK
Checking Plesk version .............................................. [OK]
Checking for custom configuration templates
Some custom configuration templates have been found. The custom
templates have higher priority than default templates in case of
configs generation.
Please check...