I also tryed commenting out the whole zzzkaltura.ssl.conf and moving all the rules including the redirect to the httpd.conf from apache but i get the same results the 400 bad request.
As an extra details the server is CentOS 6.8 and i'm configuring /etc/httpd/conf/httpd.conf
Edit: In the apache ssl error log from kaltura i can see the following:
[error] [client 89.136.235.146] PHP Notice: Use of undefined constant DEBUG_BACKTRACE_IGNORE_ARGS - assumed 'DEBUG_BACKTRACE_IGNORE_ARGS' in /opt/kaltura/app/infra/log/KalturaLog.php on line 192, referer: https://kalturassl.servcast.net/start/index.php , but i don't really think this can cause the issues with my redirect. As i can see the error if being generated only when i access the admin_console, so has nothing to do with my 400 bad request.