Hostgator should give you a command line. If they don't, then they will not work for NodeBB. Again, we recommend DigitalOcean to host your NodeBB, you'll get a month free just by registering with this link.
Yeah, I am at a loss at this point. When you run the repolist command I am not seeing it show the EPEL repository, yet when you try to install it it says you already have it.
This isn't really a NodeBB problem though, so we can't really blame the NodeBB script for it. It's almost like Yum itself is messed up. You might be able to get extra help from the CentOS community though, or if someone else here is more of a CentOS expert?
@Florian hast du den nodebb prozess am laufen?
nodebb arbeitet übrigens nicht mit port 80, sondern 4567
du müsstest also hier schauen ob es läuft: http://188.8.131.52:4567