500 internal server errore CP admin

[k23]

Server operating system version

Un

Plesk version and microupdate number

18.0.58

Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at root@localhost to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Hello...

Shows this when, from frontend of WP website, admin logged in, i click on the function the recall the DB of admin CP.
If i manually add 'index.php' After It works properly. But it s not now It Is supposed to do.
Any suggestion? Thanks