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:
This question is related to
asp.net
.net
authentication
forms-authentication
Sounds like an error you would get when your forms authentication ticket has expired. What is the timeout period for your ticket? Is it set to sliding or absolute expiration?
I believe the default for the timeout is 20 minutes with sliding expiration so if a user gets authenticated and at some point doesn't hit your site for 20 minutes their ticket would be expired. If it is set to absolute expiration it will expire X number of minutes after it was issued where X is your timeout setting.
You can set the timeout and expiration policy (e.g. sliding, absolute) in your web/machine.config under /configuration/system.web/authentication/forms
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.
I was getting this same error, in our case it was caused by a load balancer. We hade to make sure that the persistance was set to Source IP. Otherwise the login form was opened by one server, and processed by the other, which would fail to set the authentication cookie correctly. Maybe this helps someone else
I've had the same issue after using a web.config from another machine. The problem was related with an invalid MachineKey. To solve the problem, I modified the web.config to use the correct MachineKey of my server.
This MSDN blog post shows how to generate a MachineKey.
Here is a good article from Microsoft http://www.iis.net/learn/troubleshoot/security-issues/troubleshooting-forms-authentication that covers various cases and scenarios.
Source: Stackoverflow.com