Ensure the mobile phone supports NFC. Turn on the BTR5 2021 and unlock the phone. Put the NFC area of the BTR5 2021 close to that of the phone (usually there will be a dialogue popping up or a prompt tone). NFC is a near field communication technology. The NFC sensing area of the mobile phone and the BTR5 2021 must be closer enough to each other to be paired. In addition, the NFC power of different mobile phones is different (mobile phones with a metal shell have relatively low NFC sensitivity). In addition, a mobile phone wearing a phone case also has low NFC sensitivity, so it is suggested to remove the case and try again.