Loading Sign keeps spinning after on the wrist preference screen

Greetings _kay,

Thanks for visiting the Apple Support Communities! It seems you're unable to pair your Apple Watch to your iPhone.

I suggest ensuring your iPhone has the latest version of iOS: Update your iPhone, iPad, or iPod touch - Apple Support

Additionally, ensure Bluetooth is enabled on your iPhone, by tapping Settings > Bluetooth: Pair a third-party Bluetooth accessory with your iPhone, iPad, or iPod touch - Apple Support

If the issue persists, test the behavior after restarting both devices: Restart your iPhone - Apple Support & How to restart your Apple Watch - Apple Support

Cheers.