The Atempo backup software is VERY sensitive to DNS names as well as case.  In other works, it tends to be very compliant to what you would normally expect from a Linux server.  Therefore, there are (2) general scenarios where this problem manifests itself:

If the server name is not resolvable to the backup client, backup server and backup admin station - in this configuration, it is normal that the server will not be accessible via the Atempo console.  to resolve this typically you have to fix the DNS entries to match across all systems so that the name is resolvable to the right IP Address. 

If the backup client and backup server are not of the same version, connecting directly to the backup client for administration is usually not allowed - Currently, the only way to fix this is to upgrade the client to the latest version the backup server is running.  However, to work around this issue, you can manually enter in the inclusions into the interface or you can log into the GUI from the backup client (Windows only) and try to administer the settings from there.