Here are some things you can try:
1. Make sure Bluetooth is enabled on your phone. If it is, try turning it off, then turning it back on again.
2. Check to see when the last sync was. Your band is set to collect sleep information from your phone no more frequently than every 4 hours, so if 4 hours hasn’t yet passed, check back later.
3. Charge your ReadiBand by plugging it into a powered USB port. It may be that the battery is low.
5. Sign out of Readi, then sign back in.
If it’s still not syncing, contact Support. You can do this in Readi by tapping More then Help.