Alcatel 90240 with Android 7.1.1 with Zoiper 2.8.39 here.
My Diamondcard account appears to register OK.
When I try to call any destination the call window opens and then closes within a few ms. For a simple elementary test I try calls to firstname.lastname@example.org (account balance) and email@example.com (echo test). Ideas?
Th ... Peter E.