DBMS_DEBUG error

When debug a procedure if raise an error like below :


ORA-01031: insufficient privileges
ORA-06512: at "SYS.PBSDE", line 78
ORA-06512: at "SYS.DBMS_DEBUG", line 226
ORA-06512: at line 1


User does not have sufficient privileges for debugging PL/SQL
You must grant DEBUG CONNECT SESSION to your user.

--for example

GRANT DEBUG CONNECT SESSION to app_usr;