A：There are four possible reasons and solutions if your device cannot connect to other Bluetooth devices:
1. If you cannot find other phones' Bluetooth, please check if the other phones' Bluetooth is turned on and in discoverable mode.
2. If your Bluetooth headset cannot be found, please ensure that the headset is in discoverable mode (pairing mode). The operation method for entering pairing mode varies slightly between different Bluetooth headsets. Please refer to the headset's instruction manual or search online for relevant settings. Generally, alternating red and blue lights indicate that it is in pairing mode.
3. If you receive a message indicating that you cannot connect to other phones when sending files, please check if the other phones support receiving files or if they support receiving this type of file.
4. In some cases, mobile phones cannot connect to other devices due to protocol incompatibility. In this case, it is necessary to check the Bluetooth protocol support of your phone and other devices.