Though I have the necessary permissions for using SqlDependency almost memorized (as well as documented in my presentations and my new CoDe Mag article on Query Notification), I tend to forget that when using the lower level SqlNotificationRequest, that you need permissions to send and receive on your custom services and queues.

Here's how to do that and here is the MSDN Documentation on the same.

In this example, the ASPNET account is the one for IIS5 that I have set up in my SQL Server. Use whichever account is going to be accessing the services and queues.

GRANT RECEIVE ON MyNotifQueue TO ASPNET

GRANT SEND ON SERVICE::[MyNotifService] TO [ASPNET]