I have OnePlus 6T with Android 10 on it with pro version of Zoiper. And registration channel push notifications simply disappears from lock screen and appears when I unlock my phone. I chose don't optimise battery for Zoiper in settings, turned on all notifications and made them important but nothing wasn't useful. Push notifications of all other apps I can see on lock screen but Zoiper registration channel push mystically disappears. How I can fix this problem?
