case A) failed:
May 15 08:21:57 mail postfix/smtp[3123]: D06EBF994A: to=<user1@mail.example2.org>, orig_to=<user1@example2.org>,relay=mail.example.org[13.2.15.21]:25, delay=0.79, delays=0.71/0.01/0.02/0.04, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 71746C75E5)


case B) success:
May 15 08:05:17 mail postfix/local[35412]: 4E94BC75C2: to=<user2@mail.example.org>, orig_to=<user2@example.org>, relay=local, delay=1.2, delays=1.2/0.01/0/0.02, dsn=2.0.0, status=sent (delivered to command: /usr/bin/procmail -m /etc/procmailrc)