The security timestamp is invalid because its creation time ('11/9/2007 10:37:07 PM') is in the future. Current time is '11/9/2007 10:28:52 PM' and allowed clock skew is '00:05:00'.
After fixing the user's clock, which was roughly 8 minutes fast, everything worked great. The next question is "How do I increase the maximum skew time"? It took a bit of searching to figure out that I need to create a custom binding to change the values. Here is an example of how to do it:
<localClientSettings maxClockSkew="00:07:00" />
<localServiceSettings maxClockSkew="00:07:00" />
For more information, see How To: Set a Max Clock Skew on MSDN.
- Custom Bindings page on MSDN shows the proper way to stack your collection of binding elements.
- How To: Create a Custom Binding Using the SecurityBindingElement which shows how to build the a custom binding.