Bluetooth Keyboard Does Not Pair

Support & Help Requests Raspberry Pi
1

I have severe difficulty getting my Bluetooth keyboard to pair with Ubuntu Mate on my Raspberry Pi4.
Typically it asks me to enter the PIN to pair. I enter this, then nothing happens. If I try to connect, it fails. If I try to repeat the pairing, it doesn't give me the opportunity and says pairing failed.
The hardware is OK, since it pairs with some OS:
Ubuntu 20.4 -works OK
Raspbian -works OK
Mate 20.04.1 -fails
Mate 20.10 -fails mostly

Any ideas where this is going wrong ?

2

Which model of keyboard are you using?

I noticed the same behavior with my Logitech K380 keyboard on 20.10. (Not on a Raspberry Pi) I am able to reconnect after initial pairing only by putting the keyboard into pairing mode, then selecting to connect. This seems to work consistently for me. It's a little annoying that it doesn't connect automatically under 20.10, but at least it works.