I use Whatsapp on my iPhone 6 IOS 9. Sometimes the phone is silent when a new message comes in, why?

[iMore Question]

I use whats app on my iPhone 6 IOS 9. Sometimes the phone is silent when a new message comes in.

All volume controls are ok and the phone is not muted. It does not even vibrate. All settings are as they should be. Please can anybody help?

 

[Bigeric23]

Re: I use whats app on my iPhone 6 IOS 9. Sometimes the phone is silent when a new message comes in

Have you tried reinstalling the app?