Error opening pdf on 2012 server.

I have a 2012 server where non administrators receive an error "Your current security settings do not allow this file to be downloaded" wen opening a pdf. I hit this on another server and he culprit was acrobat dc trying to download an update. I fixed it on the other server by adding

key bProtectedMode to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Adobe\Acrobat Reader\DC\FeatureLockDown. That isn't solving the issue on my new server.

Any suggestions?

Thanks,

Mike