"John is a rich and important man."
Translation:János egy gazdag és fontos ember.
It would be fine to use férfi in this sentence. You can report it if it comes up again.
Férfi is specifically a man. Ember is just a person. So, férfi is really a better match for the English anyway.
I am hungarian, and i think férfi is not the best choice here. It is unnatural. We usually use "ember" for men. E.G. If you hear this: "Ő egy befolyásos ember." (He/She is a well-connected person), we always mean that: He is a well-connected man.
Then how would you say this sentence for a woman then? Is ember really generally referring to a man, so if you want to specify, you need to use "nő"?
Is it normal that it's wrong translation if I write John instead of Janos? I mean do Hungarians really call Johns Janos?
No, they don't. It was a really dubious choice for the course to "translate" proper names. If you get one of these, whether it's Hungarian→English or English→Hungarian, please report it.
I disagree. While I haven't been to Hungary a lot yet, I have never once heard "John" used there. Anyone with an English name of John gets called János. I get called "Istvan", etc. My Hungarian teacher refers to her husband (An American named John) as János.
I think it is entirely appropriate to acclimate English speakers with the Hungarian versions of proper names.
It is a bit confusing since other duolingo courses accept both, but it is true, we do not use foreign versions of names that have an appropriate equivalent.