Facing a strange issue with asp.net web application.The session values are getting lost.
The most common reason for losing session data is that your AppPool has recycled.
If you are string sesion in process, during application pool recycling you will loose session values.
The fix is to switch to out-of-process session state, such as SQL Server, or to avoid using session state entirely.
In the interim, you can disable AppPool timeouts, but it's not advisable for the long term.
If you are using web garden, you need to use either SQL server or state server to store your session variables.
Don;t forget to mark classess whose objects are getting stored in session an attribute serializable.
As application is crossing the boundries of application domain.