Apple has released watchOS 5.0.1. It fixes a glitch that wouldn’t let users close their Activity rings, as well as dealing with a charging issue.
To install watchOS 5.0.1, the Apple Watch must be on a charger, have at least 50% battery, and must be in range of the iPhone to which it’s paired. Open the Apple Watch on the smartphone, and tap the My Watch tab. Under the General section, select Software Update and enter the passcode if requested.