MATE and bluetooth headset problem

Some time ago, I bought wireless headphones Bose QuietComfort 35 II, they have nice sound, great noise cancelling and I have to say I immediately took to the comfort of having no wires attached. They connect seamlessly with Android phone, they connect seamlessly with my RHEL 8 laptop with Gnome 3, and in the past, they used to work decently with my debian/testing desktop where I have MATE. For some time, it was possible to connect using blueman-applet, even if there were some glitches every now and then. Most of them were resolved when I tried to buy a different bluetooth dongle.

At certain point of time, however, it stopped working altogether. When I tried to connect, I’d get this error:

Attempting to connect to [address] Failed to connect: org.bluez.Error.Failed

I had to leave the applet be and resort to command line.

# systemctl restart bluetooth.service
$ pulseaudio -k && pulseaudio --start
$ bluetoothctl

I had to restart the bluetooth service, then – this was probably the issue – had to restart pulseaudio. After that I was able to connect to the (already paired) headset without any issues.