500 error A callback parameter was not provided in the request URI

I can't figure out why I'm getting this.  My ajax call the web api is below:

$.ajax({
            url: '/api/FlossTotal/',
            type: 'GET',
            dataType: 'json',
            success: function (data, textStatus, xhr) {

                datasource = data;

            },
            error: function (xhr, textStatus, errorThrown) {
                return;
            }
        });

Other controllers are working ok in the project.

500 would have to be a problem with the web API right.  It's just basic as below:

public class FlossTotalController : ApiController
{

public List<FlossLinks> Get()
{

   return DBFloss.GetTopAccounts();  //this is working fine

}

<b>Stack Trace:</b> <br><br>

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<code><pre>

[InvalidOperationException: A callback parameter was not provided in the request URI.]
WebApiContrib.Formatting.Jsonp.JsonpMediaTypeFormatter.GetPerRequestFormatterInstance(Type type, HttpRequestMessage request, MediaTypeHeaderValue mediaType) +295
System.Net.Http.Formatting.DefaultContentNegotiator.Negotiate(Type type, HttpRequestMessage request, IEnumerable`1 formatters) +416
System.Web.Http.Results.NegotiatedContentResult`1.Execute(HttpStatusCode statusCode, T content, IContentNegotiator contentNegotiator, HttpRequestMessage request, IEnumerable`1 formatters) +137
System.Net.Http.HttpRequestMessageExtensions.CreateResponse(HttpRequestMessage request, HttpStatusCode statusCode, T value, HttpConfiguration configuration) +427
System.Net.Http.HttpRequestMessageExtensions.CreateErrorResponse(HttpRequestMessage request, HttpStatusCode statusCode, Func`2 errorCreator) +248
System.Net.Http.HttpRequestMessageExtensions.CreateErrorResponse(HttpRequestMessage request, HttpStatusCode statusCode, Exception exception) +171
System.Web.Http.&lt;SendAsync&gt;d__0.MoveNext() +924
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52
System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24
System.Web.Http.WebHost.&lt;ProcessRequestAsyncCore&gt;d__0.MoveNext() +418
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52
System.Web.TaskAsyncHelper.EndTask(IAsyncResult ar) +60
System.Web.HttpTaskAsyncHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +6
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9690164
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously) +155

My formatter config

        public class FormatterConfig
        {
            public static void RegisterFormatters(MediaTypeFormatterCollection formatters)
            {
                var jsonFormatter = formatters.JsonFormatter;
                jsonFormatter.SerializerSettings = new JsonSerializerSettings
                {
                    ContractResolver = new CamelCasePropertyNamesContractResolver()
                };

                // Insert the JSONP formatter in front of the standard JSON formatter.
                var jsonpFormatter = new JsonpMediaTypeFormatter(formatters.JsonFormatter);
                formatters.Insert(0, jsonpFormatter);
            }
        }