Phone can only call one extension?

[correlative]

Hello,

Got a few phones setup yesterday. They are all Yealink T21 EP2 and one W56H with the base. For some reason on the W56H it will only call one extension. How do I troubleshoot this?

 

[leejor]

What does the 3CX Activity Log show for a working call, and one that fails? Compare them. Is the failing call even reaching the PBX? Could thier be an internal (set) dialplan configuration issue? Are the sets all on the local LAN (same as PBX), all at the same site?