Cannot pair when phone changed
1.If your old phone and your new phone are having the same operating system（both are Android or iOS), you can install Amazfit App on your new phone and log in the app with the same account you used before. In this case, you can connect your device and won't lose any data. (For iOS, please make sure you have removed all the devices in the old iPhone Bluetooth settings before pairing to the new one)
If the old phone and new phone are different ( one is Android, the other is iOS ), you need to unpair the device from the app in your old phone and QR code will show up on the home screen automatically. After that, you can install Amazfit App on your new phone and log in the app with the same account you used before to pair your watch with your new phone.
2.If you forgot the username and password, please reset your watch to factory settings (Swipe down down from the watch face➡tap Settings➡tap Device➡tap Factory reset ) and then pair it with the new mobile phone.