ASP.NET

protected async void GetCasesButton_Click(object sender, EventArgs e)
{
    //#region Required Field Validation
    if (CaseNumbersTextBox.Text.Length < 1)
    {
        string myStringVariable = "Case number textbox cannot be empty.";
        ClientScript.RegisterStartupScript(this.GetType(), "myalert", "alert('" + myStringVariable + "');", true);
        return;
    }
        try
        {
        #region Get Batch Number
        int newBatchNumber = await CandidateCaseController.GetNextBatchNumber();
        #endregion
        #region Insert entered case numbers in database
			foreach (string caseNumber in userEnteredCaseNumberList)
            {
                EditCandidateCaseModel newCandidate = new EditCandidateCaseModel();
                newCandidate.CaseNbr = caseNumber;
                newCandidate.EntryStaffUserName = Helpers.Authentication.GetADEmail();
                await CandidateCaseController.PostCandidate(newCandidate);
            }
            #region Get MNCIS info on cases
            //candidateCasesString
            List<string> smallEnoughStrings = new List<string>();
            List<AcceptCaseNumbersModel> mncisDetailList = new List<AcceptCaseNumbersModel>();
            List<AcceptCaseNumbersModel> smallEnoughMncisDetailList = new List<AcceptCaseNumbersModel>();
            foreach (string smallEnoughString in smallEnoughStrings)
            {
                smallEnoughMncisDetailList = await FTACaseReseting.Controllers.JusticeController.GetAllAcceptCaseNumbers(smallEnoughString);
                mncisDetailList.AddRange(smallEnoughMncisDetailList);
            }
            #endregion
               
        }
        catch (Exception ex)
        {
            string errorMsg = string.Format("An error has occured in {0}. \nException:\n{1}", "GetCasesButton_Click()", ex.Message);
            ClientScript.RegisterStartupScript(this.GetType(), "myalert", "alert('" + errorMsg + "');", true);
        }
}

public class JusticeController
{
    #region Get
    public static async Task<List<AcceptCaseNumbersModel>> GetAllAcceptCaseNumbers(string candidateCases)
    {
        List<AcceptCaseNumbersModel> retVal = new List<AcceptCaseNumbersModel>();

        TokenModel tm = new TokenModel();
        tm = await TokenController.GetAccessToken();

        if (tm.access_token.Length > 0)
        {
            using (HttpClient client = DataAccess.EstablishConnection(ConfigurationManager.AppSettings.Get("ServiceUri"), ConfigurationManager.AppSettings.Get("ServiceReturnType")))
            {
                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", tm.access_token);

                HttpResponseMessage response = new HttpResponseMessage();
                response = await client.GetAsync("api/GetAllAcceptCaseNumbers/" + candidateCases);

                if (response.IsSuccessStatusCode)
                    retVal = await response.Content.ReadAsAsync<List<AcceptCaseNumbersModel>>();
            }
        }
        return retVal;
    }
    #endregion
}

Detailed Error Information:
Module	   WindowsAuthenticationModule
Notification	   AuthenticateRequest
Handler	   ExtensionlessUrlHandler-Integrated-4.0
Error Code	   0x80070021
Config Error	   This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".
Config File	   \\?\C:\SrcCode\IMS\Development\IMS\IMS.Web\web.config

Config Source:
   99:         <anonymousAuthentication enabled="true" />
  100:         <windowsAuthentication enabled="true" />
  101:       </authentication>

More Information:
This error occurs when there is a problem reading the configuration file for the Web server or Web application. In some cases, the event logs may contain more information about what caused this error.
If you see the text "There is a duplicate 'system.web.extensions/scripting/scriptResourceHandler' section defined", this error is because you are running a .NET Framework 3.5-based application in .NET Framework 4. If you are running WebMatrix, to resolve this problem, go to the Settings node to set the .NET Framework version to ".NET 2". You can also remove the extra sections from the web.config file.
View more information »

Stored Proc
ALTER PROCEDURE [dbo].[ValidateEmpID]
@empID varchar(50)
AS
BEGIN
SET NOCOUNT OFF;
SELECT employeeName, email, emptitle, EmpID,
    CASE WHEN YEAR(d.dateCreated) = YEAR(getdate()) -1 THEN 1 ELSE 0 END as previousYear, 
    CASE WHEN YEAR(d.dateCreated) = YEAR(getdate()) THEN 1 ELSE 0 END as thisYear 
    FROM Employees e 
    INNER JOIN dateDetails d on e.employeeID = d.EmployeeID 
    INNER JOIN SourceDetails so on e.employeeID = so.EmployeeID
	INNER JOIN SpouseDetails sp on e.employeeID = sp.employeeID 
    WHERE EmpID=@empID
 END

//HTML

  <div class="table-responsive">
    <table class="table">
    <tr>
	<td>
	<div class="form-group">
	<label for="lblEname"><span style="font-weight:bold;font-size:16px;color:#000000;">Employee Name</span><span style="color:#ff0000">*</span></label>
	 <asp:TextBox ID="txteName" placeholder="Employee name..." style="width:200px;" class="form-control" runat="server"></asp:TextBox>
	<asp:RequiredFieldValidator id="RequiredFieldValidator2" Font-Bold="true" 
	 SetFocusOnError="true" runat="server" 
	 ErrorMessage="*" ControlToValidate="txteName" /><br />
	 </div>
	 </td>
	<td>
	 <div class="form-group">
	<label id="lblTitle"><span style="font-weight:bold;font-size:16px;color:#000000;">Your title</span><span style="color:#ff0000">*</span></label>
	<asp:TextBox ID="txttitle" placeholder="Employee title..." style="width:200px;" class="form-control" runat="server"></asp:TextBox>
       <asp:RequiredFieldValidator id="RequiredFieldValidator3" Font-Bold="true" 
	   SetFocusOnError="true" runat="server" 
	 ErrorMessage="*" ControlToValidate="txttitle" />
       </div> 
       </td>
	<td>
	 <div class="form-group">
	 <label id="lblEmail"><span style="font-weight:bold;font-size:16px;color:#000000;">Your email address</span><span style="color:#ff0000">*</span></label>
	<asp:TextBox ID="txtemail" placeholder="Employee email..." style="width:200px;" class="form-control" runat="server"></asp:TextBox>
       <asp:RequiredFieldValidator id="RequiredFieldValidator4" Font-Bold="true" 
	SetFocusOnError="true" runat="server" 
	ErrorMessage="*" ControlToValidate="txtemail" />
	</div>
	</td>
    </tr>
   </table>
</div>



<table class="table">
<tr>
<td>
  <asp:gridview ID="Gridview1" RowStyle-Wrap="false" gridlines="None" CssClass="responsiveTable1" runat="server" ShowFooter="true" AutoGenerateColumns="false" onrowdatabound="Gridview1_RowDataBound" OnRowDeleting="Gridview1_RowDeleting">
    <Columns>
    <asp:BoundField DataField="RowNumber" Visible="false" HeaderText="Row Number" />
    <asp:TemplateField HeaderText="Name">
     <headerstyle horizontalalign="Left" />
	<ItemTemplate>
	    <asp:TextBox ID="txtsourcename" Text='<%# Eval("sourcename") %>' placeholder="Name...(e.g, Jane Doe)" runat="server" style="width:375px;" AutoPostBack="true" class="form-control textClass" OnTextChanged="txtsourcename_TextChanged"></asp:TextBox><br />
	    <asp:CheckBox ID="grid1Details" ClientIDMode="Static" runat="server" Checked="false" AutoPostBack="true" OnCheckedChanged="Grid1CheckChanged" /><span style="color:#ff0000">*Check this box if N/A</span>
	</ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Address">
    <ItemStyle HorizontalAlign="Left"></ItemStyle>
	<ItemTemplate>
	    <asp:TextBox ID="txtsourceaddress" Text='<%# Eval("sourceaddress") %>' placeholder="Address..." runat="server" style="width:375px;" class="form-control textClass"></asp:TextBox><br /><br />
	</ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="">
	<ItemTemplate>
	 <asp:Button ID="ButtonAdd" runat="server" Text="Add another row if needed" 
		onclick="ButtonAdd_Click" CssClass="grvAddButton" /><br /><br /><br>
	</ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="">
	<ItemTemplate>
	 <asp:Button ID="sourceDelete" runat="server" Text="Delete" CommandName="Delete"
		 CssClass="grvDelButton" OnClientClick="return confirm('Are you sure you want to remove this row?')"  /> <br /><br /><br />
	</ItemTemplate>
    </asp:TemplateField> 
    </Columns>
  </asp:gridview>
</td>
</tr>
</table>
   
//VB
Protected Sub txtEmpID_TextChanged(sender As Object, e As EventArgs) Handles txtEmpID.TextChanged
  If Not String.IsNullOrEmpty(txtEmpID.Text) Then
      Dim Conn As SqlConnection
      'Read in connection String
      Conn = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
      Conn.Open()
      Dim cmd As New SqlCommand("ValidateEmpID", Conn)
      cmd.CommandType = CommandType.StoredProcedure
      cmd.Parameters.AddWithValue("@empID", txtEmpID.Text)
      Dim dr As SqlDataReader = cmd.ExecuteReader()
      If dr.HasRows Then
	  'Employee exists'
	  dr.Read()
	  checkusername.Visible = True
	  dprocessed.Visible = True
	  If dr("previousYear").ToString() = "1" Then
	      imgstatus.ImageUrl = "images/NotAvailable.jpg"
	      lblStatus.Text = "Please verify your information for accuracy. Then complete rest of the form."
	      lblStatus.ForeColor = System.Drawing.Color.Red
	      System.Threading.Thread.Sleep(300)
	      txteName.Text = dr("employeeName").ToString()
	      txttitle.Text = dr("empTitle").ToString()
	      txtemail.Text = dr("email").ToString()
	      txtEmpID.Text = dr("empID").ToString()

	      Dim currentRow As GridViewRow = CType((CType(sender, TextBox)).Parent.Parent.Parent.Parent, GridViewRow)
	      Dim txtsource As TextBox = CType(currentRow.FindControl("txtsourcename"), TextBox)
	      txtsource.Text = dr("sourcename").ToString()
	      Dim txtsource As TextBox = CType(currentRow.FindControl("txtspousename"), TextBox)
	      txtspouse.Text = dr("spousename").ToString()                      

	  ElseIf dr("thisYear").ToString() = "1" Then
	      imgstatus.ImageUrl = "images/NotAvailable.jpg"
	      lblStatus.Text = "You have already completed this Disclosure form. Please close the form. If you feel there is a mistake, please contact Clerk at xxx-xxx-xxxx"
	      lblStatus.ForeColor = System.Drawing.Color.Red
	      System.Threading.Thread.Sleep(300)
	      txteName.Text = dr("employeeName").ToString()
	      txttitle.Text = dr("empTitle").ToString()
	      txtemail.Text = dr("email").ToString()
	      txtEmpID.Text = dr("empID").ToString()
	      txteName.Enabled = False
	      txttitle.Enabled = False
	      txtemail.Enabled = False
	      txtEmpID.Enabled = False
	      GridPanels.Enabled = False
	      dprocessed.Visible = True
	      btnNext.Enabled = False
	  Else
	      'not this year, nor the previous year'
	  End If
      Else
	  checkusername.Visible = True
	  dprocessed.Visible = True
	  imgstatus.ImageUrl = "images/Icon_Available.gif"
	  lblStatus.Text = "Proceed to complete entire form"
	  lblStatus.ForeColor = System.Drawing.Color.Red
	  System.Threading.Thread.Sleep(300)
	  txteName.Text = ""
	  txttitle.Text = ""
	  txtemail.Text = ""
      End If
  Else
      checkusername.Visible = False
  End If
End Sub