Error while reactive the physical server with deactivated server 2019OEM key

Hi Vivek S ,
Thank you for reaching out to us. We understand the issue you are experiencing and are happy to assist.
The error code 0xC004C003 indicates that the activation server has determined the product key you are using is blocked. This commonly occurs when a MAK (Multiple Activation Key) has been blocked on Microsoft’s activation servers.
To resolve this issue, please contact the Microsoft Licensing Activation Centers to verify the status of the MAK and request a replacement key if necessary. Once you receive a new, valid key, reinstall or re‑enter the product key and attempt to activate Windows again.

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Best regards,
Nam Bui

how to Contact the Microsoft Licensing Activation Centers and provide the blocked key and proof of purchase ?

Error 0xC004C003 means the activation server has blocked that product key.

For this specific error, the documented resolution is not a local fix on the server but to work with Microsoft’s licensing support to validate and, if appropriate, replace the key:

1. Collect proof of license ownership for the OEM Windows Server 2019 Standard key (invoice, COA, or documentation from the OEM/reseller).
2. Contact the Microsoft Licensing Activation Centers and provide the blocked key and proof of purchase so they can:
   • Verify the status of the OEM key, and
   • Issue guidance or a replacement key if the original has been blocked.
3. Once a valid key is provided, install it on the server and run activation again.

If the key remains blocked, only Microsoft (or the OEM who sold the server) can resolve or replace it; there is no supported workaround to bypass a blocked product key.

References:

• Troubleshoot Windows activation error codes