Mac Keyboard from iMac won't work on Imac Pro

Anyone have any idea why a WIRED iMac keyword circa 2012 won't work with 2017 iMac Pro? Thanks. Does the fact one is a regular iMac and the other an iMac Pro, with a different processor, have anything to do with it? AI says it should work.
(In case this off-topic post is TOO off topic for someone, I use the the macs and keyboards at two remote locations while working on my Davinci projects. I can present proof if needed.)
(In case this off-topic post is TOO off topic for someone, I use the the macs and keyboards at two remote locations while working on my Davinci projects. I can present proof if needed.)