No Voice on answer

[tsim]

We have two Quadro M8Ls with standardised Yealinks. The new one was cloned by restore with values (IP, names, etc) changed for the new site. The local IP phones worked well on the new M8L but the remote IP phones have no voice on answer. On the old M8L, all remote IP phones work well. Only hardware difference is that the new M8L is connected to a newer Billion adsl2+ router and settings and port mappings for SIP, RTP, STUN are similar. NAT Traversal is set to 'Force' and system detects it as 'Full cone NAT'.

The remote phones on the new M8L (with our normal deafult Yealink setting of NAT Traversal = disable) can REGISTER but cannot make any external or extension calls. Dialing *74 appears to execute but no voice. After changing the NAT Traversal = STUN in the Yealink, it now can make calls and hear the ringing tone but on answer there is no voice, i.e. 2-way no voice for both caller and destination party. However, it can receive incoming call OK. Also, *74 gets the announcement OK.

I have attached a log from SIP UA and for comparison I have lined up a good call from the old M8L and the bad call from the new M8L. IP addresses, etc have been edited to protect the identities.

Any pointers of where to investigate further or how to resolve would be much appreciated.

Best regards/tsim

[tsim]

Is there a chance for assistance in this issue? The matter is becoming urgent and appreciate some comments from members who have experienced similar issue. Thanks.

[Vahan]

The log of the "New QuadroM8L" call does not present the beginning of the call, only some SIP ACK messages. It is impossible to say anything up on this.

[Vahan]

Please attach logs starting from SIP INVITE coming from the remote Yealink phone.

[tsim]

Thanks, Vahan. I will get arrange to provide the full log and forward when completed.

[Sampratt]

From last few,Sometimes SIP service doesn't work I am able to make calls but not getting incoming calls. Can Anyone help me with the solution.