Hey Alsa
I’m sorry, but I think I can’t help much more right now. I remember having the same issue once, and it helped down/upgrading again, but I`m not sure it will help you, as you did that already.
The update process went through without any errors I assume.
So carefully checking all the logs (apache and cmk web), maybe even checking single requests on the ports itself might help. (443 - apache, 5002 - cmk). See if there is a firewall running (just stop it completely to test) or even see if SELinux is running.
Cheers Jens