The trust relationship between workstation and domain fails for ASP.NET app as soon as the connection goes down

We have an ASP.NET app which has been installed onto a Vista laptop in order to take it offsite for a demo. The app uses Windows authentication. The problem is that the moment we disconnect the laptop from the network we get the following error:

The trust relationship between this workstation and the primary domain failed.

I've seen this before when I've been screwing around with the my system clock and disconnecting from the network (which makes sense). But I can't understand why it would happen immediately the moment the network disconnects. Any ideas?

From serverfault d4nt

• Having seen someone report the same error on this forum. I found I was able to fix the problem by editing the web.config file and removing

  securityTrimmingEnabled="true"
  

  from the

  <system.web>
    <sitemap>
      <providers>
        <add . . . >
  

  node.

  From d4nt