Quick one today where I was on a client server hosted in AWS that wasn’t activated and trying to activate it via Settings App throws and error. Like most large scale cloud vendors (except Azure), AWS use KMS to activate their windows machines, however sometimes the servers need some help to reach the internal KMS servers at Amazon – especially so when using your own DNS servers.
Open an administrative PowerShell console and enter the following commands
Import-Module "C:\\ProgramData\\Amazon\\EC2-Windows\\Launch\\Module\\Ec2Launch.psd1" Add-Routes Set-ActivationSettings
Then perform an activate online command as per a normal KMS activation (or you can wait…)
slmgr /ato
And that should get it activated and the watermark removed.