upgrade activation error

[IvyX]

Hi everyone,
I'm stuck while trying to activate my Parallels Desktop upgrade license.

1. I enter my new upgrade key → system accepts it
2. Then it prompts me to enter my old qualifying key for verification
3. I enter the old key → activation fails with this error:
   "The old activation key has not yet been accepted by the license server."

Has anyone else run into this? Is this something support needs to fix on their end, or is there a workaround?
Any help would be much appreciated. Thanks!