I connected my watch before and it disconnected and I don’t know how to reconnect it
When I first got my watch I had connected it and it disconnected by itself when I got a new phone. How do I reconnect it?
Apple Watch Series 5, watchOS 9
Question marked as
Put your watch on its charger and keep it there until you complete the erase. (select the watch OS version)
Erase Apple Watch – Apple Support (UK)
Erasing all content and settings this way erases all media, data, and settings from your Apple Watch, but it does not remove Activation Lock if it has one.
Or if it is still under your iCloud account you can erase and remove it from your account in Find My or https://icloud.com/find .
Wait for the process to finish, then set up your Apple Watch again with the new iphone. Set up your Apple Watch – Apple Support (UK)
If it fails, I suggest you try to set up again as new.