I’ve been using this link to retrieve all the equipment on a character:
Of course, I’ve replaced the brackets with a character name, server and an access token.
It was working great but it started to return outdated info. It is possible that it returned the right info that one time and then it stayed that way.
You can try it yourself on the official API reference page. Once again, I’m talking about WoW Classic. (I know that’s the API for retail but it works for classic too… or at least it used to work)