A client had build an API that would return 200 on broken requests. We pointed it out and asked if maybe it could return 500, to make monitoring easier. Sure thing, next version "Http 200 - 500", they just wrote 500 in the message body, return remained 200.
Some developers just do not understand http.
The "success" is never true. If it's successful, it's not there. Also, a few endpoints return 500 instead, because of course they do. Oh, and one returns nothing on error and data on success, because, again, of course it does.
Anyway, if you want a clearer symptom that your development stack is shit and has way too much accidental complexity, there isn't any.
So it becomes entirely possible to get a 200 from the thing responding g to you but it may be wrapping an upstream error that gave it a 500.
Nice.