A little trick I've found that works...
Try and verify and watch if go down in flames. :)
Call in and type in the long code in the phone system (using the keypad on speaker, not speech recognition at I always had to keep trying over and over.
Once the automated systems starts spitting out the numbers, or if you had to talk to a human simply hang up.
Close the activation window, open it back up and it will activate now.
And yes being nice to the human is a good think, I usually just said thank you, It's activated now and then hung up.
Now this only works on real keys, it will still fail on banned keys like Devil's Own and Dell's VLK