I've used a MAK to activate several Windows Server2012 R2 machines using the automated phone system. On one machine, I enter the confirmation ID and get the "Thanks, you're all done" message, but when I check using slmgr, it still shows Unlicensed. I've tried using slmgr /atp <confirmation ID>, and get "Error: Product activation failed." I believe I am entering the correct confirmation ID, because if I change it I get an error message that the confirmation ID is invalid.

Any ideas on where to look at why product activation is failing would be appreciated!

MAKs have a limited number of activations.  Are you sure you have not used the maximum on that MAK?

Your best option is to call the activation center and talk with someone about what you are seeing.

Hi bmoranb,

Would you please let us know current situation of this issue? Any update?

I agree with Tim. MAKs by design have a limited number of activations. I suggest that you should contact the Microsoft Activation Call Center.

Best regards,

Justin Gu