I'm hitting the "error" part of this ajax call, seeing "'error in btnTestProduceUsageSettings'":

1. $("#btnTestProduceUsageSettings").click(function () {
               var dom = $('#dayofmonthselect').val();
               var ord = $('#ordinalselect').val();
               var dow = $('#dayofweekselect').val();
               var wom = $('#weekormonthselect').val();
               var daterangefromval = $('#produsagefrom').val(); 
               var daterangetoval = $('#produsageto').val();
               var unitval = $('#unitsselect').val();
               var reportId = 1;
   
   
               $.ajax({
                   type: 'GET',
                   url: '@Url.Action("GetTestSettingVals", "TestSettings")',
                   data: { unit: unitval, report: reportId, dayofmonth: dom, ordinal: ord, dayofweek: dow, 
   weekormonth: wom, fromval: daterangefromval, toval: daterangetoval },
                   cache: false,
                   success: function (returneddata) {
                       var nextgendate = returneddata.testsettings.NextGenDate;
                       var nextfromdate = returneddata.testsettings.NextFromDate;
                       var nexttodate = returneddata.testsettings.NextToDate;
   
   
                       alert('If you save the current configuration, the Produce Usage report would next be 
   sent on ' + nextgendate + ' and cover data from ' + nextfromdate + ' to ' + nexttodate);
                   },
                   error: function () {
                       alert('error in btnTestProduceUsageSettings');
                   }
               });
   
   
           }); 

JSLint doesn't find anything really wrong with it (beyond its usual nitpickiness). At least one of 

the params is always null. I wondered it that was the problem, but I tried this, just to make sure the null values were not causing the problem:

1. . . .
   var ord = ''; //$('#ordinalselect').val();
   var dow = ''; //$('#dayofweekselect').val();
   var wom = ''; //$('#weekormonthselect').val();
2. . . .

...and it still failed.

The Controller method that is supposed to be called isn't being reached at all because of the failure. It is defined:

1. public JsonResult GetTestSettingVals(string unit, int RptID, string dayOfMonthGen, 
2.                         string ordinalGen, string dayOfWeekGen, string weekOrMonthGen, 
3.                         int fromIntDateRange, int  toIntDateRange)

So stepping through the code, with a breakpoint in Chrom Dev Tools, I reach the "$.ajax({" line, but not the breakpoint in the Controller method (in Visual Studio), which has one on the last line shown below:

1.     public class TestSettingsController : Controller
       {
           public JsonResult GetTestSettingVals(string unit, int RptID, string dayOfMonthGen, string ordinalGen, string dayOfWeekGen, string weekOrMonthGen, int fromIntDateRange, int toIntDateRange)
           {
               TestSettingsModel model = new TestSettingsModel();

I have other ajax/controller combinations designed the same way that work fine, so I can't see what the hangup is here...am I missing an either obvious or well-concealed problem here?