Have a S20 and S50, both with the same issue.
Some users need to have Linkus remotely.
The PBX allows connections to 5060, 8111 and 10000-12000 only from some external IPs, so it is secure.
Nevertheless, when registering an external extension on Linkus, the extension logs in just fine, but is unable to call any number.
Not even other local extensions.
The message states: You have dialed a wrong number.
As soon as the computer running Linkus connects to the network via VPN and registers to the internal PBX IP, it is able to call any number.
Any hint as to what am I missing?