Cannot pair my keyboard again

Hi and welcome to the Forum!

I have given your post it's own thread so as to help you better without interrupting the other ongoing thread. Please start a new thread in future when you have an issue in accordance with Forum Rules. We do recognise that you are a new member and maybe having difficulty posting.

Have you connected anything else to your iPad which may still be paired?

If not try resetting your iPad and try again......this will not change anything on your iPad and is akin to rebooting a PC. Let us know how you go.
Hold the power off button and the home button simultaneously, keep holding them in and you will see the power off slide appear and disappear, wait until you see the Apple logo appear before releasing the buttons. It will take a little longer for your iPad to start.

 

If Leelai's advice doesn't work, try forgetting the device and re-pairing it. BlueTooth can sometimes be flaky.

Tap on the arrow next to the name of the keyboard in Settings/Bluetooth and hit the "Forget this device" button.