Step2 F-token generation appears to be broken with 2.5.1

[mcat1997]

As title states, Nintendo must have changed the Step2 F-API with release 2.5.1. Attempting to login under[https://api-lp1.znc.srv.nintendo.net/v2/Game/GetWebServiceToken] throws a 9403 (Invalid token) error.

[Coxxs]

I believe they have been preparing this since at least March (when 2.5.0 was released), the "check" for unofficial apps has been added since then.
A temporary fix: https://github.com/Coxxs/NSOk

[StarlightC]

It seems that they use FCM Token instead.

[JoneWang]

Fixed