ios 15.4.1 not getting third party calls and messages notification on lockscreen
I recently bought an iPhone 13 pro max. i then updated to 15.4.1 from 15.4. i then figured out that i am not receiving calls and messages ( no ringtone either) on third party apps like facebook messenger, viber, whatsapp and others, however i am getting regular calls on my phone. i am getting call and messages notification when my phone is unlocked or i am using the same app. after i lock my phone and wait sometime like 5 minutes i then again stop being notified.
I already tried all the provided solutions and whereabouts but nothing seems to work till now. i even tried a force restart and a factory reset, but no luck. is this a typical software issue? any help would be appreciated as this problem is hampering my work already.
Regards,
Roshan
iPhone 13 Pro Max, iOS 15