If PowerShell also fails, check for these specific licensing conflicts: GUI Interface Bug
Set-ExchangeServer -Identity "YourServerName" -ProductKey XXXXX-XXXXX-XXXXX-XXXXX-XXXXX Use code with caution. exchange 2019 product key invalid
Confirm your current installation status to ensure you are targeting the correct server and edition: If PowerShell also fails, check for these specific
Are you currently seeing a (like KEY_NOT_ACTIVATED ) or just the generic "invalid" message in the EAC? If PowerShell also fails
Applying a Volume License key to an installation performed using retail media can cause rejection.