I just realized that the 3cx is not displaying incoming calls on display. Phone is ringing but i have to unlock the phone and use the push notification to accept calls. Honestly i am not sure since when this behaviour exists. At Home or at Office i use my desktop phone so i never check my phone when it rings. Also realized 3CX is not requesting "Display over other apps" permission as other SIP clients (easybell, zoiper, satellite) apps does.