Hi
The following steps may help (check after each):
If you have not yet done so, update your iPhone and Apple Watch to the latest compatible software versions, starting with your iPhone:
If you have not yet done so, install any available update for the Facebook app on your iPhone (via the App Store > Updates).
If you are not yet doing so, then you might wish to use these settings:
- On your iPhone, in the Watch app, go to: My Watch (tab) > Passcode - turn on Wrist Detection.
- On your iPhone, in the Watch app, go to: My Watch > Passcode > Turn Passcode on.
- Also on the Passcode settings screen, enable Unlock with iPhone.
- After putting it on your wrist, your Apple Watch will then unlock after whatever you do first: either unlocking your watch manually (by entering the passcode) or unlocking your iPhone. It will then remain unlocked (including when the screen is asleep) until you remove it from your wrist. When you remove your Apple Watch, it will lock automatically.
Close the Watch app (if open) on your iPhone and restart both devices (normally):
If the issue persists, then it may next help to unpair and re-pair your Apple Watch: