Active Directory in ASP.net - asp.net-mvc

Question

Currently I have this error:
This happens after I modify some part of the Web.config.
This is my web.config. I don't have another idea which part of my codes do I need to add or modify to implement this active directory. I don't have background on this one.
<appSettings>
<add key="webpages:Version" value="2.0.0.0" />
<add key="webpages:Enabled" value="false" />
<add key="PreserveLoginUrl" value="true" />
<add key="ClientValidationEnabled" value="true" />
<add key="UnobtrusiveJavaScriptEnabled" value="true" />
<add key="autoFormsAuthentication" value="false" />
<add key="enableSimpleMembership" value="false" />
</appSettings>
<system.web>
<compilation debug="true" targetFramework="4.5">
<assemblies>
<add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
</assemblies>
</compilation>
<httpRuntime targetFramework="4.5" />
<authentication mode="Windows" />
<identity impersonate="false" />
<roleManager enabled="true" defaultProvider="AspNetWindowsTokenRoleProvider">
<providers>
<clear />
<add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" />
</providers>
</roleManager>
<authorization>
<deny users="?" />
</authorization>
<sessionState mode="InProc" />
<pages>
<namespaces>
<add namespace="System.Web.Helpers" />
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Optimization" />
<add namespace="System.Web.Routing" />
<add namespace="System.Web.WebPages" />
</namespaces>
</pages>
</system.web>
<system.webServer>
<validation validateIntegratedModeConfiguration="false" />
<handlers>
<remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" />
<remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" />
<remove name="ExtensionlessUrlHandler-Integrated-4.0" />
<add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
<add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
<add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
</handlers>
</system.webServer>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="DotNetOpenAuth.Core" publicKeyToken="2780ccd10d57b246" />
<bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="DotNetOpenAuth.AspNet" publicKeyToken="2780ccd10d57b246" />
<bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="0.0.0.0-1.3.0.0" newVersion="1.3.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="itextsharp" publicKeyToken="8354ae6d2174ddca" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-5.5.4.0" newVersion="5.5.4.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="itextsharp.xmlworker" publicKeyToken="8354ae6d2174ddca" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-5.5.4.0" newVersion="5.5.4.0" />
</dependentAssembly>
</assemblyBinding>
</runtime>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework"></defaultConnectionFactory>
</entityFramework>
<system.net>
<mailSettings>
<smtp>
<network host="ap.smtp.lear.com" port="25" />
</smtp>
</mailSettings>
</system.net>
</configuration>
I wanted to used this #User.Identity.Name.Remove("0,9").ToLower()
Since, i haven't set up the active directory yet so basically, this wont work.