I just got home from work, I tried the activation and it was activated from the first try. :nerd:

or you can wait for a day or two for the traffic load of the authentication servers to be normalized and try then. Besides, you have a whole month time to go back to windows 8

I tried the cmd activation and it says that the activation failed. I upgraded with the upgrade tool from win 8.1 pro to win10 pro.

I think it's normal. It's the first day of release, so the activation server is propably getting hammered