BC30451: 'DefaultAuthenticationTypes' - error.

[Blueie]

Hello

I have what looks like a serious compiler error, serious in that I cannot see any of my files in the browser. When I click on 'View in Browser', I get this compiler error:

BC30451: 'DefaultAuthenticationTypes' is not declared. It may be inaccessible due to its protection level.

That line of code is in my \App_Code\Startup.Auth.vb file and looks like this:

Click Here

The error may relate to this 'Import':

Imports Microsoft.AspNet.Identity

but all eight of my aspx.vb files include that at the top of their pages.

This is what my Web.config file looks like:

<configuration>
  <connectionStrings>

     <add name="students" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|students.mdb;" providerName="System.Data.OleDb" />
  </connectionStrings>

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.AspNet.Identity.Core" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
      </dependentAssembly>

      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

Thanks for any advice.