Apple Watch is no longer paired

The best solution here would be to remove it from your Apple ID and try to pair it again. To do this, go to Settings > [Your name] and scroll down. You should see a list of your devices, in which there is the name of your Watch. You can remove this by tapping the name and tapping "Remove device". Then, in the Watch app, you should attempt to pair it again. If this does not appear to work, pair it manually by tapping the small "Info" button on the Watch. It will give you a code to enter on your phone, at which point it should connect. Let me know how you get on.