Hi - check your settings:
- On your iPhone, go to: Settings > Notifications > WhatsApp Messenger > check that each of these is turned on: Allow Notifications, Show in Notification Centre and Show on Lock screen.
- On your iPhone, in the Watch app, go to: My Watch (tab) > Notifications > scroll down to the list of apps > turn on the button next to WhatsApp Messenger (if already turned on, try toggling off and on again).
If the settings are configured correctly, it may help to restart both your iPhone and your watch. Turn both devices off together first, then restart your iPhone before restarting your watch:
- To turn your watch off: press and hold the side button until you see the Power Off slider; drag it to turn off;
- To turn it on: press and hold the side button until you see the Apple logo.