MVC Controller throwing Null Reference Exception only when deployed, works locally

I have a fairly simple web app that is working locally, but after deploying it to a server, the controller is throwing a null reference exception. Here is the stack trace.

[NullReferenceException: Object reference not set to an instance of an object.] 
ExcelEmailImporter.Controllers.ExcelImporterController.Emails(String action) +2068
lambda_method(Closure , ControllerBase , Object[] ) +126
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +241
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext    controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +38
System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation ierInvokeState) +11
System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +138
System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +111
System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +452
System.Web.Mvc.Async.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) +15
System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +37
System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +241
System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState ierState) +29
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +111
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +53
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +19
System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState ierState) +51
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +111
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +606
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +288

The jQuery function:

$('#btnUpdate').click(function () {
var arrayOfChildren = [];
$('#EmailBody tr').each(function () {
    var childNodes = $(this).find("td");
    var childValues = []

    childValues[0] = childNodes[0].ierHTML;
    childValues[1] = childNodes[1].ierHTML;
    childValues[2] = childNodes[2].ierHTML;
    childValues[3] = childNodes[3].ierHTML;
    arrayOfChildren.push(childValues);
})

$.ajax({
    url: "/ExcelImporter/Emails",
    type: "POST",
    data: { action: JSON.stringify(arrayOfChildren) },
    contentType: "application/json; charset=utf-8"
});
});

And the Controller being used:

public class ExcelImporterController : Controller
{
    [HttpPost]
    public ActionResult Emails(string action)
    {
        if (Request != null)
        {
            if (action.Equals("UploadExcel"))
            {
                HttpPostedFileBase file = Request.Files["file"];
                if ((file != null) && !string.IsNullOrEmpty(file.FileName))
                {
                    string fileName = file.FileName;
                    string fileContentType = file.ContentType;
                    byte[] fileBytes = new byte[file.ContentLength];
                    ExcelUploadModel uploadModel = new ExcelUploadModel();
                    using (var package = new ExcelPackage(file.InputStream))
                    {
                        ExcelWorksheets currentSheet = package.Workbook.Worksheets;
                        ExcelWorksheet workSheet = currentSheet.First();
                        int noOfCol = workSheet.Dimension.End.Column;
                        int noOfRow = workSheet.Dimension.End.Row;
                        for (int rowIterator = 2; rowIterator <= noOfRow; rowIterator++)
                        {
                            EmailContentModel ec = new EmailContentModel();
                            ec.EmailTo = workSheet.Cells[rowIterator, 1].Value.ToString();
                            uploadModel.EmailContentList.Add(ec);
                        }
                    }
                    retu View(uploadModel);
                }
            }
            else if (Request.AcceptTypes.Contains("application/json"))
            {
                List<List<String>> modelDataList = JsonConvert.DeserializeObject<List<List<String>>>(action);

                using (SqlCoection con = new SqlCoection(ConfigurationManager.CoectionStrings["EmailDatabaseCoection"].CoectionString))
                {
                    foreach (List<string> valueList in modelDataList)
                    {
                        using (SqlCommand cmd = new SqlCommand("INSERT INTO EmailContent (EmailContentKey, EmailAddress,EmailFrom ,Subject, Body, EmailID, IsSent) SELECT NEWID(),@EmailTo,@EmailFrom, @EmailSubject, @EmailBody,(SELECT Count(*) FROM EmailContent),0", con))
                        {
                            var _with1 = cmd;
                            _with1.CommandType = CommandType.Text;
                            _with1.Parameters.AddWithValue("@EmailTo", valueList[0]);
                            _with1.Parameters.AddWithValue("@EmailFrom", valueList[1]);
                            _with1.Parameters.AddWithValue("@EmailSubject", valueList[2]);
                            _with1.Parameters.AddWithValue("@EmailBody", valueList[3]);
                            try
                            {
                                con.Open();
                                cmd.ExecuteNonQuery();
                            }
                            catch (SqlException ex)
                            {
                                con.Close();
                            }
                            con.Close();
                        }
                    }
                }
                retu View();
            }
        }
        retu View();
    }

    [HttpGet]
    public ActionResult Emails()
    {
        ExcelUploadModel newModel = new ExcelUploadModel();
        ViewBag.Message = "Import emails from excel.";

        retu View(newModel);
    }
}

Again, this works locally but I'm lost as to what's causing this on the server. Thanks for any help/advice!