Login failed for user: The user is not associated with a trusted SQL Server connection

This is your first project? Am i right? Yes almost 50%(my guess) Asp.net beginner got the below message while he run his project. The message is:Login failed for user ''. The user is not associated with a trusted SQL Server connection. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error