Server Error in '/' Application.

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:

1. Add a "Debug=true" directive at the top of the file that generated the error. Example:

  <%@ Page Language="C#" Debug="true" %>

or:

2) Add the following section to the configuration file of your application:

<configuration>
   <system.web>
       <compilation debug="true"/>
   </system.web>
</configuration>

Note that this second technique will cause all files within a given application to be compiled in debug mode. The first technique will cause only that particular file to be compiled in debug mode.

Important: Running applications in debug mode does incur a memory/performance overhead. You should make sure that an application has debugging disabled before deploying into production scenario.

Stack Trace: 

[NullReferenceException: Object reference not set to an instance of an object.]
   TLC.TLO.Client.Controls.Header.GetLegSessList() +193
   ASP.controls_header_ascx.__Render__control1(HtmlTextWriter __w, Control parameterContainer) +423
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +275
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +79
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +168
   System.Web.UI.Page.Render(HtmlTextWriter writer) +39
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +79
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4238

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4797.0