Most of the issues described in this thread sound like NAT issues. 99% of issues customer experience are related to routers/NAT. What happens in some cases is that the router lets the "signaling traffic" through but then when the audio stream connections on a different port it blocks it thinking it's unrelated or "malicious traffic". Many routers to try to be smarter than they are basically.

This can usually be connecting our device directly to your modem (if it doesn't have a router built in) or by assigning a static IP to the device and setting up port forwarding for ports 5004-65000 UDP to it.

Ultimately there's nothing we can do to force traffic through a router except help you configure the router to handle it. Issues that are sporadic are even more likely to be NAT related like this because the ports are randomly chosen and sometimes (when it works with no issues) we could be in one port range and then other times (when you have issues) it's in a different port range that the router doesn't like.

99% of the time it's NAT/routers that cause issues. Our support team can try to help you diagnose, but if you are having issues and don't setup port forwarding it's almost 100% guaranteed that you'll continue to have them.