Not connect. verify network in jquery ajax function

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ASP.NET

Ajax

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var data_pass = "{cityid:'" + cityid + "', status:'" + st + "', inboxstatus:'" + inst + "'}"
           $.ajax({
               type: "POST",
               url: path + "/function_name;, // active_hotels is an function of above webservice file
               data: data_pass,
               contentType: "application/json; charset=utf-8",
               dataType: "json",
               success: function (result) {

                     alert("success");
                
               },
               failure: function () {
                   alert("fail");
               },
               error: function (jqXHR, exception) {

                   if (jqXHR.status === 0) {
                       alert('Not connect.\n Verify Network.');
                   } else if (jqXHR.status == 404) {
                       alert('Requested page not found. [404]');
                   } else if (jqXHR.status == 500) {
                       alert('Internal Server Error [500].');
                   } else if (exception === 'parsererror') {
                       alert('Requested JSON parse failed.');
                   } else if (exception === 'timeout') {
                       alert('Time out error.');
                   } else if (exception === 'abort') {
                       alert('Ajax request aborted.');
                   } else {
                       alert('Uncaught Error.\n' + jqXHR.responseText);
                   }

               }
           });

This coding return the Not connect.\n Verify Network error. I am using web service with calling bulk of data from sql server. i doesnt know what is mean "Not connect" error in this ajax. if anybody know pls reply.