The header pretty much says it all. My WAN attached endpoints and softphones have dial tone, touch tone, can call an extension/phone number and hear it ring. But when the call is answered, no voice can be heard. My network guys says all of the required ports are open.

Because you say ports I suspect you are nat'd you need your nat address in the 5000 or you have no audio try 6000 connection group and add nat address
Randy

You'll love this. I tried every NAT combination (our firewall doesn't like anything but itself maintaining NAT control). I tried changing the Auto/Native/NAT settings. Nothing worked. All programmable settings for the softphone and endpoint were identical to other endpoints on the system. I copied all settings from a random endpoint and copied them to the softphone and endpoint connected by WAN. Voila! They worked. There was something, not available in the programming, that wasn't working. Go figure.

Good to know next time I run into one I'll try a Copy / paste. Had a new 86XX IP phone give me the same issues today came right up but no audio, after dbl and tripple checks finally a second reboot of the phone fixed it? Don't think I'll sleep well for a few days have no doubt it will come back and bite me next time it resets