I did charge the Nikon battery to full and left it in the camera for a few hours....same thing when I turned it on....Oh well, it was something to try.

I'll try that before I send it back, thank you

I just received the new Nikon Battery and it does the same thing.   Cleaned the contacts...no change.   Guess it's going back.   Thanks for your help though.

I just bought a used Z6, as an upgrade to my old 5300.   It didn't come with a battery.   I've now bought two sets of Amazon aftermarket batteries.   The first said it was for a host of Nikon cameras and the second said it was specifically a replacement for the 15B battery.   When I put any of the four in my new camera (which I haven't been able to verify even works yet), I get an error, specifically  "This battery cannot be used.   It does not communicate properly with this camera.   To use the camera safely, choose a battery designated for use in this camera."    

I have the specific Nikon battery coming...who knows when it will get here, but everything I read tells me it should accept at least some of these batteries.

Is this normal?   Could it be due to a change in software?  Could it be a problem with the camera software?

Thanks for your time.