Hi SD,
If your license is retail or volume (VL), you're generally allowed to transfer it to new hardware. Since the original server is inaccessible and conventional deactivation isn’t possible, you can proceed with activating the license on the new server. Microsoft does not require deactivation from the old machine in such cases.
Here are a few steps to consider:
Attempt activation on the new server using your existing product key.
If activation fails, you may need to contact Microsoft Support for manual activation assistance.
Be prepared to provide proof of license ownership and details about the failed hardware.
Please note: If your license is OEM, it is tied to the original hardware and cannot be transferred. In that case, a new license would be required.
I hope this helps.
Harry Phan.