How to save a trigger of a table A in scheme A in another table B of scheme B?

I need to save some data in a Bitacora table when I update the Salary attribute, the detail is that the Bitacora table is in a DA user and the Salary attribute belongs to the Employee table which is in the AD user, then I show the trigger that I program where the Employee table is, however it shows an error in the line INSERT INTO bitacora saying that the Bitacora table does not exist, nevertheless I gave AD permissions to insert in the user or DA schema.

 create or replace trigger beforeUpdateSalary
 before insert or update of salary
 on employee
 for each row
 BEGIN
     INSERT INTO bitacora 

(id_bitacora,nom_esquema,nom_tabla,nom_campo,fec_cambio,valor_anterior,valor_actual)
values(s_bitacora.nextval, 'AD','EMPLOYEE','SALARY',sysdate, :old.salary,  :new.salary);
END beforeUpdateSalary;