I am being prompted to enter a serial number after entering my Adobe ID

I'm experiencing a similiar problem. After downloading and installing from the manager, the program opens up as a trial version, which then asks for me to put in a serial number. I was under the believe that Creative Cloud needs no serial number. After attempting to get help from Tech Support via the chat, both representatives gave me roundabout answers, including one that said something about "24 hour activiation"? This is very frustrating. Along with work, I'm beginning to feel that I lost money behind this.