My understanding is that the "appeal to authority fallacy" is specifically about appealing to irrelevant authorities. Quoting a physicist on their opinion about a physics question within their area of expertise would make an excellent non-fallacious argument. On the other hand, appealing to the opinion of say, a politician or CEO about a physics question would be a classic example of the appeal to authority fallacy. Such people's opinions would represent expert evidence in their fields of expertise, but not outside them.

I don't think the poster's description makes this clear and it really does suggest that any appeal to authority at all is a logical fallacy.