I entered my own email address en clicked send code, but did not receive any code. Or at least, it didn’t make it to my mail program. I finally went to look via webmail and then I found (several) mails with a code.
After entering that, and clicking “activate” I was able to enter the license key. After that you get an additional screen asking for your name, email, etc. and after providing those, Power-User was activated.
Hope this helps.
To Lavantu: perhaps you are using some kind of ad-blocker or other app that blocks the connection?