A trigger is defined on a particular table. Only the owner of the table has CREATE TRIGGER and DROP TRIGGER permissions for the table. These permissions cannot be transferred to others.
SQL Server accepts a trigger definition that affects tables you do not own, and attempts actions for which you do not have permissions. You must rectify the permissions or drop the trigger. For example, Joe owns the sales table and creates a trigger on it. The trigger is supposed to update titles.ytd_sales when sales.qty is updated. However, Mary is the owner of titles and has not granted permissions on it to Joe. When Joe tries to update sales, SQL Server detects the trigger and Joe's lack of permission on titles and rolls back the update transaction. Joe must either get update permission on titles.ytd_sales from Mary or drop the trigger on sales.