2.10 Auto Logoff

I just did a clean install of NopCommerce 2.10 for a new eCommerce store. I did not install any sample data and I am using the default orange theme. For some reason I keep getting logged off from the admin section and redirected to the login page in both IE9 and IE8. The browsers are on two different computers. Is there a setting somewhere that specifies the time out period? I checked the web.config and timeout is set to 43200 (the default), sliding expiration is set to true. Any help or tips on where to look to fix the problem are appreciated.

Cordially,

Joshua

Have a look here: https://www.nopcommerce.com/boards/t/11780/login-issue-in-21.aspx#48471

setting the machinekey in web.config as specified in DVL's  post fixed the issue for me as well. For anyone else having the same issues you can use this code project sample to generate the required element and paste right above the <pages> tag
http://www.codeproject.com/KB/aspnet/machineKey.aspx

Thanks to Andrei for the Code Project link and to DVL for linking my question to his post.