Fails to register after last update, no error code

Question

Zioper won't register now since the last update. (2.14.8 - Library rev. v2.10.8.4) On both my phones. Samsung, HTC. I have uninstalled and redone the whole setup. And for that one time it works. But when I re-start the phone/app later. Zoiper won't re-register thereafter. There is no error code. I've been using the app for years.