Why does my Apple Watch re-lock within a few seconds of my unlocking it?

[Kjulie]

I upgraded my iPhone this afternoon. Since then, the watch won't stay unlocked. I have been trying for hours. Have rebooted the watch, and the iPhone. I have turned bluetooth on and off; have turned airplane mode on and off. The one thing I have not done (yet) is completely unpair and erase all the AppleWatch info and re-pair it.

I'm not sure which AppleWatch I have, but it was purchased in December 2015.

 

[Just_Me_D]

Via the Watch app, go to My Watch → Passcode, and then select "Turn Passcode Off".

 

[Mac Guy]

Via the Watch app, go to My Watch → Passcode, and then select "Turn Passcode Off".

And then turn it back on. If that doesn't fix it, I'd un-pair and re-pair it.