Hi @Razoe,
If you’re getting “Internal Server Error Occurred” then one of the HTTP requests KMC makes is failing. This means there must be a request in the “Network” tab that returned with HTTP 500. Please look carefully.
In parallel from a root shell on the server, run:
# . /etc/profile.d/kaltura*base.sh
# kaltlog
And look at the errors outputted to STDOUT.
Also, just to be on the safe side, restart your Apache and make sure it starts correctly. I’m suggesting this because you say /opt/kaltura/log/kaltura_apache_errors*.log is empty.