Hi,

we are running a mailman service along with our mail server and recently we have noticed one institution gets lots of bounce messages like below and unable to find the route cause. if any inputs really appreciated. some cases mails are partially delivered but not to all members.

Error

List: Comphealth_all Member: og-haicu-user@domain.com Action: Subscription deaktiviert. Reason: Excessive or fatal bounces.

og-haicu-user@domain.com: service unavailable. Command output: SMTPclient: unexpected reply: 571 571 Sender is not allowed to email this distribution list: og-haicu-user@domain.com_

ING@domain.com: service unavailable. Command output: SMTPclient: unexpected reply: 571 571 Sender is not allowed to email this distribution list: ing@domain.com_ Reporting-MTA: dns; mta01.domain.com X-Postfix-Queue-ID: 50A0C318A89 X-Postfix-Sender: rfc822; comphealth_all-bounces@listen.domain.com Arrival-Date: Tue, 27 Apr 2021 15:02:32 +0200 (CEST)

Final-Recipient: rfc822; og-haicu-user@domain.com Original-Recipient: rfc822;og-haicu-user@domain.com Action: failed Status: 5.3.0 Diagnostic-Code: x-unix; SMTPclient: unexpected reply: 571 571 Sender is not allowed to email this distribution list: og-haicu-user@domain.com_

Final-Recipient: rfc822; ING@domain.com Original-Recipient: rfc822;ing@domain.com Action: failed Status: 5.3.0 Diagnostic-Code: x-unix; SMTPclient: unexpected reply: 571 571 Sender is not allowed to email this distribution list: ing@domain.com_

Von: Mara Lena Kieke mara.kieke@domain.com Betreff: Aw: [Comphealth_all] MUDS seminar Wed April 28, 3pm: Razieh Nabi Datum: 27. April 2021 um 15:02:31 MESZ An: comphealth_all@domain.com