Client unable to locate server

Windows 8 UrBack client can’t find Centos 7 Server, even though i can connect to the web interface of the server. Anybody know why this could be happening, I’ve checked all the other threads, but none of the solutions work, or the problem is entirely different. Some help would be much appreciated.

The debug log on the client says ‘Access Denied’ when i try to open it, so I can’t even tell what the client’s doing.