I am having issue in connectivity, sometimes it happens that my phone is on and signal strength is full but if someone calls me on cellular network he gets the answer that the phone is switched off even if I tried to use mobile data that also have connectivity issue and no sms received. It solves when I call on any number from my side then I am able to receive calls and sms. The issue occurs on both sims so it won't be network issue.
please restart your phone daily. i have a51 also. sometimes it also occurred in my phone but when I turned on auto restart option the issue was resolved
