We just installed the 3CX 10 SP3 and have 50 Polycom 550 to install. The Phones provision and you can dial 999 and you hear the audio. If I try to call from 1 phone to another phone, no ring and eventually dumps into voicemail. Tried with the 3cx softphone same issue. This is all on the same lan and running on Server 2008R2. Any help would be much appreciated.