MK8 video fix; signing in to MKTV does not work

When trying to share a highlight on MKTV, you have to sign in, which I did – to unsuccessful dissapointment. The webpage reads a little bit like this:

Unauthorized sign in; the app you are using no longer works with these (a list of pieces of code (?)) if you are the creator of this app, please fix this.

Yeah… I have no idea what this is

I don’t believe uploading videos to YouTube is supported yet. Don’t think that’s exactly a priority atm (plus, clips would be limited to 60 seconds long which I think is dumb imo).

I’m assuming the error message is to do with the Google sign in prompt because you’d allow Nintendo Network as a connection which was able to upload YouTube videos back in the day.