ajax-api request/response

I am designing an api, which will be called from my front end. say I have a controller method  that calls some other third party api process results and returns json response to the front end ( see sample code below) .

if there is an error in the reques/response and the request is unsucessful to the 3rd party apis, what is best approach. should I return empty json response to the front end , after handling and logging exceptions.

or is it better to send some message so that it can be dealt on the front end. if so can someone share some sample code for this. ?

//get method in some controller
public ActionResult GetData()
{
try
    //call other apis
    //if the response is successful
           return data;
    //if unsucessful
          // ?? what to return to the front end ??
catch
      //log exceptions    
}

front end code ----------------------------------------

$(document).ready(function () {
            $.ajax({
                type: "GET",
                url: "//somecontroller//GetMethod",
                data: param = "",
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: successFunc,
                error: errorFunc
            });

            function successFunc(data, status) {    
                           //process json data
            }

            function errorFunc() {
                         //do something
            }
        });