Do what @ExpertGem said and enter the code from the email. If you don’t receive their email, there is a way to force it:
Okay, so, I found a solution for people who just don’t receive their verification emails
Note: This only works when you can access account settings page (so no SSSL Wii U)
- Access account settings to where you can change your email
- Change it to the same email
a. If this didn’t work, change it to some other email and then again to the email you want.
What this does is “re-trigger” the email being set and thus sends it out again.