Activating Win 2012 product key gave 'Software Licensing Service reported that the product SKU is not found'

Select Plus      Windows Srv 2012 DataCenter MAK C      
YYYYY-XXXX-YYYYY-XXXX-YYYYY      MAK

I got the above licence product key from the procure dept
(which I've masked out)

When I tried to register the above key in our Win2012 DC VM
by issuing the command
  slmgr -ipk YYYYY-XXXX-YYYYY-XXXX-YYYYY

it gave the following error:
Error: 0xC004F069 on a computer running MS Windows non-core edition,
Run ‘slui.exe 0x2a 0xC004F069’ to display the error text.
Description:
The Software Licensing Service reported that the product SKU is not found.

When I run the above slui command, it gave:
Error: 0xC004F050 The Software Licensing Service reported that the
      Product key is invalid


I've googled for a few links: my VMs have joined the domain, so this
is not the reason.

I tried the following  but can't locate the update/patch for Win2012:
http://workinghardinit.wordpress.com/2012/08/17/windows-server-2012-kms-service-activation/
  which leads to
http://support.microsoft.com/kb/2757817


Then I tried another key below from procurement (with key type KMS, the
earlier one was key type MAK)  but this time it gives the message
'Error: 0xC004F050 The Software Licensing Service reported that the
 product key is invalid'
Select Plus      Windows Srv 2012 DataCtr/Std KMS
AAAAA-BBBBB-CCCCC-DDDDD-EEEEE      KMS


I've also tried to create another VM with server core running
Win2012 Standard edition & it gave exactly same errors as the above.

I've checked that my VMs is only 2-3 minutes' different from the
Ntp & I've also set the timing on the VMs to be the same as Ntp
but no joy

Any ideas?