/series/247854/images/query?keyType=Fanart is the relative url for getting the fanart of a specific series that has fanart, but it returns 404.
https://www.thetvdb.com/series/health-and-physical-education-for-30-year-olds is the series page.
It returns other image types as expected, and other series (there are probably more that error, but this is the one I found) return as expected, as well.
It doesn't just return 404, but it gives the no results found message, so it's definitely the right url.
I don't know what to think other than, "it's a bug." Does anyone have any idea?