bluetoothd connect error: Connection refused (111)

Problem

bluetoothd[978]: connect error: Connection refused (111)

It's because the device have already paired with another OS with same dongle.

Solved

$ bluetoothctl

#[bluetooth] remove XX:XX:XX:XX:XX:XX

#[bluetooth] quit

$sudo systemctl restart bluetooth.service

$ bluetoothctl

#[bluetooth] scan on

#[bluetooth] pair XX:XX:XX:XX:XX:XX

#[bluetooth] trust XX:XX:XX:XX:XX:XX