As a user of Adobe products for over ten years, it’s a bit aggravating when they stop supporting some of their older products. I recently tried to de-activate my Adobe Audition 3 and it gave the the message that “activation server is not available.”
I ended up chatting online with a person, they have also stopped their phone support, and it turns out that to get Audition 3 to work on a new computer that I have to go to a CS2 downloads page and download a new version with a new serial number. I’m guessing that this version doesn’t have Activation requirements
and here’s the page for the CS2 downloads and Audition 3.