conn / as sysdba;
alter session set container=cdb$root;
select username, account_status 
  from dba_users 
 where username in ( 'APEX_PUBLIC_USER', 'APEX_REST_PUBLIC_USER', 'APEX_LISTENER', 'ORDS_PUBLIC_USER' )
   and account_status <> 'OPEN';

alter user APEX_PUBLIC_USER identified by <Ваш пароль без окружающих угловых скобок> account unlock;

select name, open_mode 
 from v$pdbs
 where name <> 'PDB$SEED';

alter session set container=name_из_запроса;

select username, account_status 
  from dba_users 
 where username in ( 'APEX_PUBLIC_USER', 'APEX_REST_PUBLIC_USER', 'APEX_LISTENER', 'ORDS_PUBLIC_USER' )
   and account_status <> 'OPEN';

/* Изменение паролей и разблокирование пользователей */
...

create profile APEX_AUX limit PASSWORD_LIFE_TIME unlimited;

alter user APEX_PUBLIC_USER profile APEX_AUX;