Hi All, I am having an issue with my 3CX version 12 system where if I dial one of extensions assigned to a Yealink SIP-T26P from the windows softphone the line lights flash up on the Yealink for an instant but there is no ringing on from the Yealink or the softphone and then after 20 seconds the call get forwarded to the voicemail system. I can successfully make softphone to softphone and Yealink to softphone calls without an issue. All external bound calls from either softphone or the Yealink work OK as well. We also have some polycom conference phones and the softphones can call them fine. Has anyone else experienced this before and managed to resolve the issues?