Apple Watch activity and workout not working

Me too, happened now after update to watchOS 7. I have Apple Watch series 5. Phone is ios14.

My problem started after I started a workout. After that it wasn’t registering any more activity at all. I can’t start activity, it’s just black and nothing showing up.

It was also draining my battery very fast. All was out after a couple of hours. I saw the green light against my wrist was continuously glowing, guess that drained the battery out. After it was drained I put it at the charger and was hoping the problem was solved when being complete shutdown, but problem is still there.

So far I’ve resolved performing a factory reset, and uninstalling Strava once the restore has been completed.

I have been facing related issues with activity in Apple watch too. Please see: https://discussions.apple.com/thread/251807094

Same here with AW series 4 right after the update both hearth rate and gps signal are not working.

Strava or fitness app is the same, hope we’ll be able to rollback

I solved it with unpairing the watch and then pair it again, worked directly after that!