Whether your asp.net application access any com+ components, in that case you can take a look at below link on how to can avoid timeout issues,
An ASP.NET application may experience delays if a request times out when the application invokes in-process COM+ components
http://support.microsoft.com/kb/917069
Otherwise, try setting Connection Timeout property to a higher value in your web.config file and similarly if you are using Command Object to execute queries/sp then setting CommandTimeout property of Command object too and see whether it helps!
Is your webserver and database server are the same?
Asp.net - SQL Server Database Timeouts
Take a look at the below article for ways to avoid database timeouts error,
http://www.sqlserverandxml.com/2006/07/aspnet-sql-server-database-timeouts.html |