Audio problems are usually an issue pertaining to a connected NAT device (i.e. router). On devices that we've set up, we take care of most of the issues for you. A couple of things that can still cause problems are DMZ and port forwarding being enabled on your router simultaneously. Another setting that can be disabled that usually causes degraded audio issues is the SPI (Stateful Packet Inspection) Firewall.

 Please make sure that ports 5060-5080 TCP/UDP and 5004-65000 UDP are allowed to pass by customizing forwarding rules within your router. Since RTP (audio) works on different ports than SIP (signaling) then you can register fine but still have issues with audio.

Also, upgrading the firmware on your router to the latest version will make sure that the router is up to date with the latest  VoIP traffic handling.  Some manufacturers have firmwares that do this for you automatically, but others require it to be a manual process.

If your issue is still not resolved, please contact support toll free at 877-99-VOIPO or via email at support@voipo.com

In addition, we'll put a SIP trace on your line for the next couple of days so that we have verbose logs of the SIP signaling for reference.