SqlTableDependency onchange event not fired

I finnally found error in my sys.transmission_queue table: An exception occurred while enqueueing a message in the target queue. Error:

15517, State: 1. Cannot execute as the database principal because the principal "dbo" does not exist, this type of principal cannot be impersonated, or you do not have permission.

Even though the database already I gave myself full permission, I had yet to do

ALTER AUTHORIZATION ON DATABASE::secret db TO sa