What to Do if You Can’t Sign in to My Nintendo on iPhone December 23, 2016

Nintendo offers the My Nintendo website as a free rewards site for Nintendo players on the Wii U, 3DS and SmartPhones.  If you’re playing an app like Super Mario Run or Miitomo on the iPhone, linking your My Nintendo account to the apps can award you exclusive new digital content.

However, there seems to be some kind of glitch in the website for anyone who used it on the iPhone before installing the newer version of iOS 10. The site can start randomly redirecting the user once they arrive on it, eventually ending in an Access Denied message.  The user can’t back out of it and they can’t log back in. This can be especially annoying if you’re trying to access your My Nintendo account to link it to Super Mario Run, as the app simply uses its mobile website for login rather than providing its own integrated login functionality.
If you’re having this issue, there is a solution.  You must access your iPhone’s Settings app, select the Safari tab, and select the option to Clear all History and Website Data.  Once you do this, the My Nintendo website should begin to function normally again  This has the side effect of deleting all of your online passwords, forcing you to have to log back in to all of your online accounts.

Nintendo and Apple should take a closer look into this bug and see why it’s happening.  Until that happens, hopefully this tip helped you.