whatsapp messages not displaying when samsung s7 edge mobile locked(mainy during night hours)

[Android Central Question]

I bought samsung s7 egde last week. Whatsapp messages are getting daytime even my mobile is locked..but i noticed when i wake from sleep in the morning,no whats app msg notification showing. When i open whatsapp immediately all msgs with their actual send/received time will display...

 

[chanchan05]

Are you connected to wifi or mobile data?