postfix reject message problem. Is it my problem or other's mail server?


i having the following error in the mail.log log file.

Aug 30 11:40:53g postfix/smtp[18167]: 3EE79836A7:,[]:25, delay=79, delays=76/0.14/1.9/0.43, dsn=5.7.1, status=bounced (host[] said: 553 5.7.1 Sender address rejected: not logged in (in reply to RCPT TO command))

Does anyone know who’s fault is that? Is my mail server the problem or the receipient’s mail server ?

Plz help.

thnx a lot