We have a BT Cloud VOIP phone system with DECT and yealink landline phone :
- From DECT or Yealink, calls work from outside to inside and inside to outside.
- From DECT to Yealink or Yealink to DECT, calls work from internal to internal. (Via short number)
-From Yealink to Yealink, internal calls do not work. There is a blank call.
Do you know where this is coming from?
All ports are open and the SIP ALG is disabled. We have performed a diagnostic through capture and saw correctly Ethernet frames SIP during internal calls.