Server 2025 Evaluation Version not activating

Hi all, in my test environment I have a fresh server 2025 build (eval version), but not matter what I do I can't get it to activate to allow the 180 days. 

Following the information on the Windows Server 2025 Eval website: https://www.microsoft.com/en-us/evalcenter/evaluate-windows-server-2025 I have done everything as instructed apart from: 

"Evaluation versions of Windows Server must be activated over the internet in the first 10 days to avoid automatic shutdown."

Searching for an answer online only brings up how to activate a purchased license which is NOT what I want to do. I want to activate the 180 evaluation days.

How can I do this please?