Hello,
Thank you for posting in Microsoft Community forum.
Based on the description, I understand your question is related to windows server activation.
Firstly, please check the specific version of your key matches the machine, for example, Server 2024 standard machine should be activated by the Server 2024 standard product key, not a Server 2024 datacenter product key.
Also, you can try use below commands to do the activation again.
slmgr /upk
slmgr /ipk <your product key>
slmgr /ato
Have a nice day.
Best Regards,
Molly