Windows Server 2012 R2 gives the following error in the Event viewer:
Installation of the Proof of Purchase from the ACPI table failed. Error code:
This occurs after you have registered Windows and regularly each day thereafter. It happens because although Windows is successfully registered, there are a number of places that Windows Server 2012 registration happens and there was likely a fault or corruption installing the proof of purchase in at least one of those locations.
To fix this, do the following in an elevated cmd prompt:
Restart Windows Server 2012 R2
You will then have to re-register Windows
I’ve also tried simply running slmgr /rilc to fix this.