If your application displays the error "Connection to database has timed out.", it often means the database operation is taking longer than the default timeout period. This commonly occurs when a SqlDataReader is performing heavy processing or returning a large result set.

If you have an ASP.NET 4.0 website and need to host a separate ASP.NET 2.0 application inside its folder structure, you may run into configuration conflicts. ASP.NET applications inherit settings from parent web.config files unless explicitly told not to. This can cause runtime errors, version conflicts, or unexpected behavior.