SQL & PL/SQL

hello guys
i have got this problem, i hope someone can help me to understand and solve it.

I have a pl/sql procedure where is referenced a table on a db_link. I own all the grants needed, and if i recall it in an anonymous block, it seems to work.

i.e

create or replace procedure routine_1 is
v_app varchar2(1);
begin
select 'x'
into v_app
from other_user.some_table@my_db_link
where rownum<2;
end routine_1;




Instead, while recalling it from a job scheduled with dba_scheduler package, with the same user, while opening the cursor where the db link table is referenced, i got a connect error:

ORA-01017: invalid username/password; logon denied
ORA-02063: preceding line from xxxxxx (where xxxxxx is the db link)

i would like to understand where i am mistaking. I already checked the user for the connection in the scheduled job and is the same of the anonymous block call.

thanks in advance
Claudio