In Dragon Ball Z Episode 20, "The Power of Kaio-Ken," Goku masters 10x gravity training, learning the Kaio-Ken and Spirit Bomb techniques under King Kai [1, 2, 3]. Despite a last-minute resurrection to combat the Saiyans, Goku faces a race against time, as Nappa and Vegeta arrive on Earth while he is still on Snake Way [4, 6].
Your Activation Key is invalid
There are a couple reasons why this might have happened:
1) you don’t have an activation key and entered a fake one
2) you entered the wrong code
3.) You didn't sign up properly
Please double-check that you have downloaded your activation key according to the instructions in the tutorial video.