Internal Server Error after updating

SOLUTION:

Add the following code to the file /etc/apache2/apache2.conf and then restart apache. (from the console or from hestia)
If you use the Nginx proxy it also works.

<Directory />
    AllowOverride ALL
</Directory>

Or also:

<Directory />
    AllowOverride none
</Directory>

If you use Webmail with Snappymail you can solve the problem by running the following command in the console to change the permissions:

chown -R hestiamail:www-data /etc/snappymail/data