Fix this need the role below:

GRANT aq_administrator_role TO db_user

There is laso other grant commands may need:

E.g:

GRANT EXECUTE ON SYS.DBMS_AQ TO db_user;

GRANT aq_user_role TO tenuser1;

GRANT EXECUTE ON dbms_aqadm TO db_user;

GRANT EXECUTE ON dbms_aq TO db_user;

GRANT EXECUTE ON dbms_aqin TO db_user;