Can't access to back and front office

[MrNastykilla]

Like title says, can't access to front or back office. 500 Internal Server Error occurred at Tab title of a browser. Then:

Internal Server Error

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

Please contact the server administrator at postmaster@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.

 

Before my few ? actions, website worked perfectly.

 

My actions that could change or made this error: 

1. Switching SSL certificate option at Panel. URL pages are not validate/verified. (Just clicked at switches to see will it allow it.)

2. Customizing / inserting <p></p> in <> source code option, for content text in Panel.

3. Can't access to other apps.

 

httpd-vhosts.conf

 

<VirtualHost *:80>
    
    DocumentRoot "C:/xampp/htdocs/presta/"
    ServerName localhost
    
</VirtualHost>

 

It happened it to me already once, but it somehow fixed itself :/ Thank you for replies.