Running latest version of 3CX. My line registers with InPhonex just fine (passes firewall checks) and am able to make outgoing calls but am not able to receive any incoming calls. Nothing even appears in the log (set to verbose) so I have to imagine that it's a registration issue, but again, the line seems to register just fine. Here are my scenarios: When 3CX is registered and I call my number from my mobile phone the call rings, goes silent, then disconnects or I get a fast busy signal. Status on InPhonex is disposition = cancelled for these calls. When 3CX is not registered (3CX server shutdown) and I register XLite with InPhonex and make the call from my mobile phone the call is completed and XLite rings. Both of these scenarios are run on the same machine that is receiving a DHCP/NAT address. STUN server seems to be resolving the external IP Address correctly. Does anyone know of any configuration issues with InPhonex that I need to be aware of or have an idea of what I can check?? Thanks, Scott.