We have a webapplication , which use FormsAuthentication mechanism for login. The application was working fine in .Net 2.0 version and recently it got migrated to .Net 4.0 and then onwards some users are getting logged out of the application which browsing through it. There is no particular pattern for this. Here is the sessionstate and Forms Authentication tags defined in web.config file.Any help will be much be appreciated.
Server Version :- Win 2008 Server
IIS version :- 7
<sessionState cookieless="UseCookies" mode="InProc" timeout="120"/>
<authentication mode="Forms">
<forms timeout="120" name=".ASPXFORMSAUTH" loginUrl="login.aspx" defaultUrl="~/Default.aspx"/>
</authentication>