Q: No vibration/sound from push notification (Whatsapp/SMS)

Hello Y-S Toh,

Thanks for using the Apple Support Communities!

I understand that WhatsApp isn’t working as expected and you have already completed some amazing troubleshooting, but the issue continues. To continue the troubleshooting process, I suggest reading over the following article to ensure that all steps have been completed. If this issue is still unresolved, you may need to contact the developer of this app, as described in the article, for further information on the situation. 

If an app you installed unexpectedly quits, stops responding, or won’t open - Apple Support

Cheers!

Hi Y-S Toh,

Thanks for replying with this extra information. If you are experiencing intermittent sound from more than one application, the next troubleshooting steps I would suggest are located in the following article. 

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

Best!