Trouble Pairing, set up Watch, no internet.
First ensure you un-paired it from the old iphone.
Read through the whole response.
Then check you have no other sports watches like Fitbit that are paired to your iPhone
Then force restart the watch. i.e. press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo.
Then Force Restart the paired iphone
Force restart iPhone – Apple Support (UK)
Then in the iphone, Settings, General, Transfer or reset iphone, Reset, Reset network settings. Then reconnect the iPhone to Wi-Fi.
Make sure you have no VPN or VPN based adblocker in the iphone in Settings, General, VPN & Device Management.
Then reset the router to factory settings which usually involves a paperclip on a little hole.
Try again to pair the Watch.
Some users have successfully turned off Wi-Fi and used the iPhone’s 5G.
Series 1 to 3 are difficult to pair with iOS16 because of relatively low storage but…
- Ensure the iphone is on iOS16.3 or later
- Erase the Watch completely. Put your watch on its charger and keep it there until you complete these steps. (select the watch OS version) Erase Apple Watch – Apple Support (UK)
- When pairing do not try to restore the backup, pair as a New Watch
Apple Resources
Click: How to pair your Apple Watch with a new iPhone - Apple Support or
Click: If you can't pair an Apple Watch with your iPhone - Apple Support or
Click: If your Apple Watch isn't connected or paired with your iPhone - Apple Support