Postfix is denying sending mail to a handful of users

[Jan Albrecht <jan.albrecht@gmail.com>]

Hi all,

I've got a strange problem here:
I connect via IMAP to my mailserver (which is also my rootserver). On
this server Postfix is delivering the mail.

If I send the mail to 5 users it works perfectly.
If I send the mail to 20 users (BCC), postfix does this with the mail
adresses:

Jul 10 18:58:32 xxx postfix/smtpd[450]: NOQUEUE: reject: RCPT from
xxx.t-ipconnect.de[xxx]: 554 <xxx>: Relay access denied; from=<xxx>
to=<xxx> proto=ESMTP helo=<xxx>

Has anyone an idea why this does happen?

I've already raised the limit:

~# postconf -d | grep smtpd_recipient_limit
smtpd_recipient_limit = 1000

but it seems that it does not work.

Has anyone of you an idea?

Regards

Jan