I have the same problem as Queequeg; "I have an active subscription for Parallels Desktop for Mac Pro Edition for two computers - renews on August, 2021. I have two Parallels Desktop for Mac Pro Edition license keys. However, I can only use one of those keys to successfully activate Parallels Toolbox. If I use the second key I get the "The product license is not accepted by the license server" message. If I use the first key on the second computer, it will tell me that license has already been activated on a different computer and asks me if I want to de-activate on the other computer and use it on this computer. That Toolbox activation works if I say 'Yes' but I then have it de-activated on my second computer. How do I fix this and have Parallels Toobox activated on both computers?"
Regards, Johan