The CUCMBE is ready to relate with PrivateServer using the SIP Trunk, but still it can't until we create the same configuration on the PrivateServer itself.
If you came here then all the necessary prerequisites are matched.
You can refer to PrivateServer management documentation for creating a SIP Trunk. We are going to explain here which specific values need to be set up in order to create it properly.
In the fig. X you can watch a plain example of a working configuration. It's major differences from a standard one is that: