We have been trying to debug a situation where Zoiper inot a SIP VOIP provider is having the following issues:
- Sometime fails to connect
- Most commonly connects, but one side or the other can not hear.
- Connects, but does not report the connect on on the calling side.
- Connects, and we can hear each other, but the call only lasts 30 seconds.
What we have done to try to resolve:
- Windows Firewall is turned off.
- Anti virus is turned off
- Windows firewall forces 5060, 10000-20000 ports to be inbound and outbound without blocking.
- Ports 5060 and 10000-20000 are forwarded directly to the win 8.1 computer.
- Stun has been turned on
- Stun has been turned off
- Installed an entirely different computer (Win Tablet) with same failures
- Installed on a cell phone locally connected to the network, with 100% success, but not something we can use.
- Installed on an entirely different computer at an entirely different state in the USA, and everything works.
- Installed linPhone, and it works out of the box. But, we do not want to use it.
We are at a complete loss. We have spent three days trying to fix this with no solution from ourselves or the provider.