My problem is the following:

I have created a procedure, in which I assign roles to users. For example:

SET serveroutput ON;

declare
vsqlsql varchar(360);
permiso varchar(360):='PROBA';
BEGIN

            vsqlsql:='GRANT '||UPPER(permiso)||' TO ueueue001';
             EXECUTE IMMEDIATE(vsqlsql);
            
END;
/

--DROP PROCEDURE ROL;

create or replace PROCEDURE          ROL (permiso in VARCHAR2)
AS

vsqlsql varchar(360);
BEGIN

            vsqlsql:='GRANT '||UPPER(permiso)||' TO ueueue001';
             EXECUTE IMMEDIATE(vsqlsql);
            
END;
/

exec ROL('PROBA');

select * from dba_role_privs where grantee='UEUEUE001' AND GRANTED_ROLE='PROBA';

Everything is correct, until I execute the procedure and it tells me:

Procedimiento PL/SQL terminado correctamente.

Procedure ROL compilado


Error que empieza en la línea: 28 del comando :
BEGIN ROL('PROBA'); END;
Informe de error -
ORA-01924: el rol 'PROBA' no se ha otorgado o no existe
ORA-06512: en "IVAN.ROL", línea 8
ORA-06512: en línea 1
01924. 00000 -  "role '%s' not granted or does not exist"
*Cause:    Either the role was not granted to the user, or the role did not exist.
*Action:   Create the role or grant the role to the user and retry
           the operation.

GRANTEE                                                                                                                          GRANT ADM DEL DEF COM
-------------------------------------------------------------------------------------------------------------------------------- ----- --- --- --- ---
UEUEUE001                                                                                                                        PROBA NO  NO  NO  NO 

When I execute the block the role is assigned correctly, but when I call the procedure it tells me that the role does not exist.

Why?