Phone: UnitData WPU-7800-v2.2.10
The phone connects fine via our wireless router to our 20mb fibre line. I accept or make one call then the phone shows as offline on the portal but the phone is still connected as I can make outgoing calls.
Everything was fine for over a year up until a few days back.
Making calls works because the phone has our server on it. So when you initiate a call, it looks for sip1.freshphone and finds it.
When receiving a call, our server doesn't know where your phone is as it is not registered any longer. This would be something on the internet router that is blocking it. Either the Firewall, or you must disable SIP ALG on your router, or your router might just need a simple restart