Windows Activation Issue After Formatting: Previously Valid Key Not Working

[Windows Server]

I recently formatted my computer and tried to activate Windows with my product key, but it says the key is invalid. Before formatting, the key worked perfectly fine. I've read that it may need to be removed from the previous device, but since I did a full format, I can't access the old installation to do so.The reason I formatted was due to severe lag while gaming. I have the product key saved separately, so I didn’t enter it during the initial Windows installation. After completing the installation and setting up programs, I tried to activate Windows, but it keeps saying the key is incorrect.

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