Hi @Thom Blues ,
I suggest you verify the KMS key in host computer, please follow these steps:
From an elevated command prompt on the KMS host computer, run the following command:
cscript slmgr.vbs /dlv all
To view information only for Office 2016, specify the Activation ID after the /dlv parameter. For example:
cscript slmgr.vbs /dlv 98EBFE73-2084-4C97-932C-C0CD1643BEA7
Then post the output text here, you can check if the License Status: Licensed.
Then I suggest you refer to this article about "configure DNS for activating volume licensed versions of Office by using KMS":
https://learn.microsoft.com/en-us/deployoffice/vlactivation/configure-dns-to-activate-office-by-using-kms
Make sure the DNS is configured correct.
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