Q: My Apple Watch locks everytime the screen turns off.

Hi

Check your settings.

• On your iPhone, in the Watch app, go to: My Watch (tab) > General > turn on Wrist Detection.
• On your iPhone, in the Watch app, go to: My Watch > General > Wake Screen > turn on Wake Screen on Wrist Raise.

Check also that you are wearing your watch sufficiently snugly. If worn too loosely, your watch may believe that it has been removed from your wrist. With passcode also enabled, it would then lock automatically. Sensor performance can also be affected by temporary or permanent changes to your skin, such as by some wrist tattoos.

If you have not yet done so, it may help to update your iPhone and watch to the latest software, starting with your iPhone:

• Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
• Update the software on your Apple Watch - Apple Support

More information:

Wearing Apple Watch - Apple Support

https://help.apple.com/watch/#/apd748b87e2a

The following further steps may also help:

• If passcode restrictions are enforced on your iPhone, they also affect your watch. If this applies, contact your device administrator for further information and help.
  • Restrictions may be applied on your iPhone via a corporate configuration profile, mobile device management or Exchange policy (as used, for example, by some schools and businesses).

• Restart both your iPhone and your watch:
  • Close all open apps on your iPhone:
    • Double-click the Home button, then swipe up on each app preview to close it.
  • Turn both devices off together, then restart your iPhone first;
    • Restart your iPhone, iPad, or iPod touch - Apple Support
    • Restart your Apple Watch - Apple Support

• Unpair and re-pair your watch:
  • The Watch app on your iPhone takes a backup of your watch automatically when unpairing via the app. Choose to Restore from Backup during set up. Most data and settings will be restored, with some exceptions (eg Apple Pay cards, passcode).
  • Unpair your Apple Watch and iPhone - Apple Support
  • Set up your Apple Watch - Apple Support