I Can’t pair my IPhone 12Pro Max with my IPad.

How to pair my IPhone 12 Pro Max with my iPad?

I turned off both devices, then turned on again and I went to settings to activate the Bluetooth and shows up both devices discoverable one of each other, check the wifi on in both devices, but when I click to pair them it just pop up a message saying that I have to make sure that my devices are in range and turn on. It doesn’t make sense because when I just activated my IPhone this was already paired with my iPad and for some reason they got unpaired. This is annoying...