Q: activity app sharing just spins

Hi

The following steps may help:

• Both users: check that your watch is connected to the paired iPhone via Bluetooth, whilst the iPhone is also connected to the Internet via cellular data or Wi-Fi.

• Both users: restart both your iPhone and your watch, turning both off together, then restarting your iPhone first:
  • Restart your iPhone, iPad, or iPod touch - Apple Support
  • Restart your Apple Watch - Apple Support

• Allow a short time afterwards for Activity data to be shared (perhaps allow an hour or so).

Otherwise, it may help if you each unpair and re-pair your watches, again allowing time afterwards for data to be shared:

• The Watch app on your iPhone takes a backup of your watch automatically when unpairing via the app.
• Choose to Restore from Backup when offered the option during set up. Most data and settings will be restored, with some exceptions (eg Apple Pay cards, passcode).
• Unpair your Apple Watch and iPhone - Apple Support
• Set up your Apple Watch - Apple Support