Hi,
With the new Ios14.3 (with Iphone X) I got also the uncomfortable feature that Whatsapp is not working i.e. delivering messages or pushing notifications IF I´m not using the app. Desktop Whatsapp goes "Phone not connected"-mode as soon as I leave the mobile app.
I have already gone through the basics, push notifications are allowed and apps are allowed to work in background.
Open WhatsApp > Settings > Notifications >
Check if you have not selected Non of any of the above.
On iPhone
Change alerts
To add or change an alert style for a notification:
WhatsApp is not an Apple product. Contact the app developer here --> App Support or WhatsApp FAQ Or Restoring your chat history - WhatsApp FAQ or Contact WhatsApp
I know it is not apple product but this behavior started after IOS upgrade...before that everything worked just fine.
And yes all the things you suggested in the first answer are taken care of and checked also.
Ios14.3 issues with Whatsapp, not getting messages or notifications IF NOT using the app
