Unable to pair bluetooth speaker "Failed to pair: org.bluez.Error.AlreadyExists"
Solution 1:
What helped me was to restart the Bluetooth service.
When I did sudo service bluetooth status I saw error info in red:
Unable pair since another pairing is in progress
and another one
B4:6C:47:53:FF:86: error updating services: Device or resource busy (16)
So I did sudo service bluetooth restart and then I was able to pair the device.