Bluetooth pairing problem on Opus keyboard

I tried to connect a Lenovo tablet via Bluetooth with an Opus keyboard model OP-ETUIBUNIV9101

First it asked me on my tablet to copy a code onto the keyboard but it didn’t work, issue with the shift key not activating properly.

After 2 different codes proposed, my tablet asks me to provide the PIN code for pairing, but I can’t find any reference to this code on the brand’s site/manual.

0000 and 1234 don’t work otherwise it’s not fun :)

Afterwards the keyboard wouldn’t sometimes blink during pairing attempts, I don’t know if that’s normal.

The worst is that I managed to connect the keyboard to my phone because they re-propose a code on my phone that I just have to copy onto my keyboard.

But on my tablet they keep asking for the PIN code. I have uninstalled and reinstalled the tablet’s Bluetooth software, nothing works, same issue. The keyboard isn’t listed among the previously connected devices with my tablet so I can’t even remove it from the history.

I’d just like my tablet to re-propose codes to type in and it would work, I’ve proven it with my phone.....

Thank you if you find anything to help !!