We experience an issue where a Queue agent answers an inbound call… but does not hear the caller (silence).
The caller at that point still hears the Music on hold. After 20 seconds or so… the agent & caller are able to hear each other suddenly.
Try setting RTP keep alive to 1 in Asterisk SIP Settings (it’s 0 by default)
and make sure that on your firewall the RTP ports are forwarded to your PBX
Thanks for helping out.
It seems the issue was simply caused by someone who has set the “Agent delay” setting on one of the Queues where the agent was in.