Parallels 10 - Can't transfer license key to new Mac

Hello,
i can't transfer the license Parallels 10 from the old mac to new one; I forgot do Sign-out on the old mac. It says that I exceed the maximum number of license in use (on new mac).
Now i have old mac with new Parallels 12 installation with newly purchased licenses (not upgrade), works without problem.
I still need to use/migrate the old license Parallels 10 with a new mac. Now i have 2 macs and 2 licence (v10-migrated from 9, v12 newly purchased).

Can you please reset the key for Parallels 10?

Thanks for help.

 

@VaclavS1 Hi there! Please check your private message and provide us your activation key.

 

We have made changes to the activation key. Please follow the instructions below:
1. Quit Parallels Desktop, then try to activate after launching it again.
2. If you are still unable to activate, Open Terminal on the Mac and execute this command: prlsrvctl activate-license-online