JS visibility of a callback inside a callback?

Question

JavaScript

I have a code (chrome extension) that i don't understand due to js specifics

chrome.runtime.onMessage.addListener(
  function(message, sender, sendResponse)
  {
    $.ajax({
      url: "http://some.site"
      ,type: "POST"
      ,data: message
      ,success: function(data)
      {
        sendResponse('что-то не работает');
      }
    });
    
    sendResponse('работает');
  }
);

Why is sendResponse('something not working'); does not work? I suspect that I am trying to call sendResponse in the wrong context.
How should this code be read correctly?
And how to achieve that the success callback from Ajax could call sendResponse?