Whenever technology goes wrong, the first thing you should normally do is “restart your device,” which, in most cases, will fix the issue.
In most cases, even the best technician will not have the answer as to why this fixes the problem.
But who cares, as long as the problem is fixed.
If that doesn’t work, you can use a forced restart to regain control.
To use the force restart for your Apple Watch, all you have to do is press and hold both the Digital Crown and the side button together for roughly 10 seconds. At some stage, the Apple logo will appear on the screen of your watch—this indicates the watch is rebooting.
Now, with any luck, the reboot will have cleared up any issues you may have had, and you’re good to go.
How to force restart and reset your Apple Watch:
In the event that an app stops responding on your Apple Watch, you can choose to force quit the app instead of restarting the entire device.
Next time you find yourself looking at the spinning circle and waiting for minutes on end, you can try this:
Press and hold the side button in (the button that is just below the Digital Crown) until the shut-down screen appears.
Let go of the side button and then press and hold it again.
After a few seconds, there will be a brief animation that will return you to the app, but then it will go to the home screen of your watch. The end result is the app being closed.
Apple Watch: How to power on, off, and hard reset: