For the record:
If you ever encounter this error while upgrading Apache webserver 2.2 to 2.4:
Unknown Authz provider: from
Code language: JavaScript (javascript)
Then you probably made a mistake replacing:
allow from all
Code language: JavaScript (javascript)
with
Require all granted
Code language: PHP (php)
And just replaced allow with Require and not the complete directive, like:
Require from all
Code language: JavaScript (javascript)
Then its time for a double facepalm :)