Please check below WEB pages first.

Assume below picture is your setting:

And below picture still displays the system using the default Registration address:

You can use the VoIP configuration to set the right proxy to solve this problem. If you use the “Quick Start” function to establish an account that you need to input the right registrar address again. If you only use one service provider and you will not encounter this problem. Because the VoIP Quick Start WEB page will read and display the first registration server of SIP service provider.