Start here: make sure the SugarPixel app is up to date in the App Store or Play Store, and that your SugarPixel Mini/Classic has the latest firmware installed. See Firmware Update.
- Connect to SugarPixel Mini/Classic in the app
- Go to Menu → Reset → Reset Bluetooth
- On your phone, remove the saved SugarPixel Mini/Classic device
- Pair again from the app using the 6-digit code