When you install Windows 11 on a new VM, the activation servers treat that as installing Windows on a new PC.
Open the Settings App.
Go to System - Activation.
Click the Troubleshoot button, then select 'I changed my hardware', and that process should be able to reactivate Windows on the new VM.
If that process is not successful, that is the only re-activation process available, you will need to contact Microsoft Support directly to get your Windows licence activated on the new VM.