What if the phone cannot connect with the Xiaomi Watch S3?

If your watch can not connect to the phone, you can check the connection status of the mobile network. If normal, you can try turning off the Bluetooth switch of the mobile phone system and turning it back on. Then, retry to continue the pairing process;
2. If your watch fail to pair the watch with the phone despite connection, please check if you allow paring timely or cancel it by mistake;
3. Reset the device or perform the Factory reset on the watch.
Note:
If the device is left idle for some time and the Bluetooth of the phone is turned on or off, it will not be able to reconnect successfully and needs to be restarted for recovery. Please update the watch to the latest firmware version to restore normal use.