ORA-28001:la contraseña ha caducado no reparable

Suponiendo que Oracle DB (también debería funcionar para SAMPLE de Oracle-XE) está en Unix, ssh-in y:

sqlplus /nolog

SQL> connect / as SYSDBA
Connected.

SQL> SELECT username, account_status FROM dba_users WHERE ACCOUNT_STATUS LIKE '%EXPIRED%';
# ... your locked account should be listed ...

SQL> ALTER USER sample IDENTIFIED BY sample;         
User altered.

SQL> ALTER USER sample ACCOUNT UNLOCK;
User altered.

SQL> ALTER PROFILE DEFAULT LIMIT PASSWORD_LIFE_TIME UNLIMITED;
Profile altered.

SQL> exit