LogFAQs > #961186931

So apparently I've made a mistake with my Nintendo account. I set up 2-step authentication, which uses the Google Authenticator app. They also give you a list of backup codes.

Well, I tried signing in using the authenticator, failed. I tried using one of the backup codes, failed. I looked it up online and apparently switching phones can screw the whole process up (I switched phones earlier this year after I set it up initially), and it looks like the only way to fix it is to contact Nintendo's customer service, so that should be fun.