Click Settings.

2.

Click to search for Bluetooth devices.

3.

If available devices keep spinning or Bluetooth devices can't be found, please turn off Bluetooth and wait for some time to start or turn off the phone to restart. There is another possibility. Maybe no one around you can turn on Bluetooth.

4.

Click to search for Bluetooth devices.

5.

Maybe it's the Apple system. I suggest upgrading the system.

6.

If you still can't connect, please turn on the Bluetooth option to find the connected device.

7.

The connected device was cancelled.

8.

You can also turn off your phone and then restart it.