==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):  0.9.6
- Deployed with iRedMail Easy or the downloadable installer?  private ssh session
- Linux/BSD distribution name and version: centos 7
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): mysql
- Web server (Apache or Nginx):apache
- Manage mail accounts with iRedAdmin-Pro? no
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hello,
i have troubles receiving from one of my customers. we are able to send mail.
in the mailog i find this:

Sep  4 08:49:12 mail postfix/smtpd[19474]: NOQUEUE: reject: RCPT from static.227.243.216.95.clients.your-server.de[95.216.243.227]: 554 5.7.1 <someuser@mydomain.it>: Recipient address rejected: Blacklisted; from=<someuser@customerdomain.it> to=<someuser@mydomain.it> proto=ESMTP helo=<mail.customerdomain.it>

i also find this in /var/log/iredapd
Sep  4 08:49:12 mail journal: iredapd [95.216.243.227] Reverse client hostname is blacklisted: .clients.your-server.de
Sep  4 08:49:12 mail journal: iredapd [95.216.243.227] RCPT, someuser@customerdomain.it -> someuser@mydomain.it, REJECT Blacklisted [sasl_username=, sender=someuser$

Any advice for solving this issue ?

Kind Regards.