.net - ASP.NET Forms Authentication failed for the request. Reason: The ticket supplied has expired

Question

I am getting this error many times in the event log and users are logged out.

Event code: 4005
Event message: Forms authentication failed for the request. Reason: The ticket supplied has expired.
Event time: 3/10/2011 3:35:22 PM
Event time (UTC): 3/10/2011 8:35:22 PM
Event ID: fc2f70cc85014b0ca7dbb01471617b66
Event sequence: 3392
Event occurrence: 1
Event detail code: 50202

Thoughts:

• I am not using web forms.
• I do not think the app pool is recycling.
• I compared the Process ID in several events and it is equal.
• My machine key is not AutoGenerate.

Answer 1

AS Scott mentioned here http://weblogs.asp.net/scottgu/archive/2010/09/30/asp-net-security-fix-now-on-windows-update.aspx After windows installed security update for .net framework, you will meet this problem. just modify the configuration section in your web.config file and switch to a different cookie name.