First off, I verified that my headphones are in pairing mode.
Trying to connect them via the Bluetooth GUI, the Settings gets stuck and is not responding. Therefore I decided using the bluetoothctl tool and followed the steps of this thread with no avail:
Attempting to pair with 04:8C:9A:EF:8C:93
Failed to pair: org.bluez.Error.AuthenticationCanceled
Maybe this log will help: using the sudo systemctl status bluetooth I get:
● bluetooth.service - Bluetooth service
Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
Active: active (running) since Thu 2021-02-11 10:36:47 EET; 23min ago
Docs: man:bluetoothd(8)
Main PID: 4588 (bluetoothd)
Status: "Running"
Tasks: 1 (limit: 19036)
Memory: 1.3M
CGroup: /system.slice/bluetooth.service
└─4588 /usr/lib/bluetooth/bluetoothd
(....)
bluetoothd[4588]: Pair device timed out for hci0