Incoming calls not working for all providers

[enes.avdic]

I recently upgraded to v12 from v10 and before I have never had problems but since upgrading to v12 people that have verizon (maybe others too) when they call in they can not hear any audio. My representative can hear the caller with verizon but the verizon caller and not hear my representative. I have tested with tmobile, att, sprint, land lines, all are ok except verizon mobile callers. Is there something in this new version that I am missing? I have no idea what to look for. I should mention that this audio problem only happens when calling one specific DID when calling a different DID everything is ok. I have checked settings between the two and everything is the same as far as I can tell, what am I missing? Thanks to anyone who takes time out of their day to help me out.

 

[sigma1]

This is a odd one! One way audio is usually a firewall NAT issue but this would be not limited to only one carrier if it was purely for your final SIP provider. I will admit that Verizon is still our biggest headache but I would like to offer you a few suggestions:

Force only G711u remove all other codecs from your SIP trunk

Let your SIP trunk provider know, in the past we had something like it but the only issue was the lack of "ringning" sound for the caller due to early media. It is likely that your provider re-invites your call for RTP to their actual provider and they may have the solution. You can also get a PCAP using wireshark form your 3CX server and that will help.