Mailaddress from certain server gets blocked - Spam Config Problem?

[Kolab, User]

for testing purpose i removed within /etc/postfix/main.cf:

content_filter = smtp-amavis:[127.0.0.1]:10024
smtpd_recipient_restrictions = permit_mynetworks, 
reject_unauth_pipelining, reject_rbl_client zen.spamhaus.org, 
reject_non_fqdn_recipient, reject_invalid_helo_hostname, 
reject_unknown_recipient_domain, reject_unauth_destination, 
check_policy_service unix:private/recipient_policy_incoming, permit

and restarted postfix. No change. mails from the froxlor server are 
still blocked. any idea?

thanks.