Third-party keyboard not connecting to iPad after iOS 15 update

Hello, there is a problem with my third party keyboard connecting to my ipad. I bought a keyboard which is able to be connected and charget through the pins on the back on the ipad. since the update ipados 18 it's not working. I tried an original keyboard and everything worked well. I also tried the keyboard I have on my friends ipad (which had an old ipados at that time) and it also worked well. Is tthere some setting I could change, for it to work once again? Thank you for the answer.

[Re-Titled by Moderator]