I have the same error since the upgrade to 1.8.10.
I tried the ‘Directory’ solution and for now it works again, though I think “AllowOverride All” might not be a good idea.
I’ve seen in the apache logfiles that the “real” error causing this was something like
“'IfModule is not allowed here”
So I assumed that there is an typo somewhere in a configuration, but as I did no change by myself I thought it must be somewhere else in any default templates maybe.
Do you have a good explanation why the ‘Directory’ is helping here and really solving the cause of the error?
If it’s wordpress site:
First Enable debugging on wp-config.php
Find out what is DB name of your site.
go to Hestia cpanel > DB > find the database username related to that website, change database password > go back to database wp-config file, changed password > saved.