Android push notifications not working

Hi

I have bough “Lenovo Tab 4 8” and cannot make notifications work. I have tried both Ring and RapidRing apps. I have tried uninstalling/reinstalling apps. I have tried clearing cache/data. I have ensured push notifications are enabled in menu. I have verified App Permissions. I have disable battery optimizations for apps. I have disabled Doze mode in android.

All other app notifications are instant (i.e. Skype, Facebook), but Ring app is still silent. My Pixel phone receives all the notifications (ring button, motion), but not the tablet.

Any ideas?