After launching EC2 instance from Windows AMI from different network/CIDR, you may need to reactivate Windows.
Route print
Check if the Route table refreshed and showing new information
Import-Module "C:\ProgramData\Amazon\EC2-Windows\Launch\Module\Ec2Launch.psd1"
Add-RoutesSet-ActivationSettingsmgr /atohttps://aws.amazon.com/premiumsupport/knowledge-center/windows-activation-fails/