Parallels 11 Won't Let Me Upgrade To Windows 10

Hi. I received Parallels 10 OEM when purchasing a Mac. I installed Win 7 using my genuine Win 7 DVD. I then paid for the upgrade to Parallels 11 for the sole purpose of upgrading to Windows 10. After following directions, downloading and running the file, it installs and then asks for a Key for Win 10. The upgrade to Win 10 is supposed to be free and I already entered in my Win 7 key when I installed that.

Why am I running into this problem. The Windows 10 upgrade is supposed to be free is it not?

 

Hello,
Please follow steps suggested at http://kb.parallels.com/122884 to upgrade to Windows 10 virtual machine.