Hi Pavit,
I've just gone through the procedure again and I'll write the steps just so we know that we're on the same page.
1) I went to components drop down menu and selected JA Multilingual
2) I then clicked on the options button and got the following screen attached
3) As you can see, I don't have a field for the API code - only one for a 'Bing client ID' This is different to the page shown in the joomlart demo where there is also a 'Bing secret client key' which I assume is where the API code is entered. As I said previously, this field flashes up and then disapears
4) So, I then return to the 'translate' tab. The Hungarian language is checked and I hit the 'translate' button.
5) The programe states 'done' but nothing has been translated. Interestingly at the bottom of the screen it says 'waiting for engl...'
Are you able to see the 'secret client key' when you are in the back end? I assume that you can because the problem can't be replicated. If it is visible is it possible to cut and paste the API code into the field box. Just a thought.
Best regards,
Kingsley