Unable to OAuth with account that owns YouTube channel

Question

I have a google account that I was previously uploading videos to using the v2 YouTube API. This account I guess has two accounts linked to it, because when I go through OAuth f

Answer 1

I was able to resolve this.

It turned out I needed to do the OAuth with the 2nd account, the one for the YouTube channel. Despite it not requesting any permissions related to YouTube and only getting offline access, I was able to successfully upload using the refresh token I received.

Definitely a case of the most illogical solution being the correct one.