I want to use Zoiper / Zoiper Beta to connect to my callcentric account. I downloaded the app and after I registered I came across the following problem: Incoming calls do not work if Zoiper registers over LTE. I tried the same over Wi-Fi and 3G and it works.
Moreover I tried the common suggestions like enabling "run in background" and enabling "4G" under supported networks. Nothing seems to allow me to receive incoming calls over LTE.
What could be the cause of this?