Is your Apple Watch failing to turn on its screen when you raise it, display notifications from your iPhone, or even update the time zone? watchOS has four modes accessible from Control Center (swipe up from the bottom of the screen) that are useful but can cause confusion if you forget to turn them off:
Silent Mode: In Silent mode, your Apple Watch won’t make any sounds, but will provide haptic feedback you can feel on your wrist.
Theater Mode: When in Theater mode, your Apple Watch not only turns on Silent mode, it also keeps the screen dark unless you tap the screen or press a button.
Do Not Disturb: As with Theater mode, enabling Do Not Disturb turns on Silent mode and prevents notifications from lighting up the screen.
Airplane Mode: Invoking Airplane mode turns off the Apple Watch’s Wi-Fi and Bluetooth radios, and the cellular radio if your watch supports that. Without Wi-Fi and Bluetooth, the watch can’t communicate with your iPhone and will thus miss notifications and time zone changes.