When driving around city I lose registration to mobile app

Question

Although I move between WIFI and Cellular connectivity very well in most cases, periodically I find that when driving I have lost registration, and even when I get to a strong signal area it doesn't re-connect.  I have the free Zoiper version.  Any ideas?

Answer 1

Are you using a VPN ?
What version of android are you using and what model of phone ?

Does it eventually re-register within the next 10 minutes ?

We have investigated similar reports in the past:
The network is probably not completely up when we try to connect after receiving the network change, the registration fails.

This happens for example if you use a vpn and zoiper is informed about the network change, but the VPN is not up yet and once the vpn is connected, there is no new "network change" event.