I'm trying to activate my new license for Server 2025 DataCenter via Volume Activation Tool (VAT) as an Active Directory-Based Activation (ADBA). I have several licenses activated this way already. Currently, I'm running VAT on a Server 2022 instance. However, every time I try to activate—either through the phone or online—I get a message saying the software licensing service reported that the product key is invalid. I've heard that sometimes there are restrictions based on the OS of the server you're using for activation, but from what I've gathered, Server 2022 should work for activating Server 2025. Is there anything I might be overlooking?
2 Answers
Are you sure you're using the correct key? You’ll need the CSVLK key for this process. Also, make sure your Server 2022 is fully patched and up to date—sometimes missing updates can cause activation issues.
In my experience, I’ve had no issues activating Server 2025 from my 2022 DCs that have the VA role for ADBA. It sounds like your setup should work fine. Maybe double-check the keys you're using to ensure they're correct.

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