When adding Office 2016 product keys to KMS – The specified KMS product key is invalid, of is unsupported by this version of VAMT. An update to support additional products may be available online.

Add Office 2016 Key to KMS server:

In order to add the KMS you need to install the Microsoft Office 2016 Volume License Pack

1. Download the Microsoft Office 2016 Volume License Pack  fro here

 https://www.microsoft.com/en-us/download/details.aspx?id=49164

Follow the steps: 

Click Yes

Enter the Product Key

Open VMAT to see the new office 2016 product key

Good luck!

Idit Bnaya