Hello, I am facing problems receiving mails from a domain (outlook /office365), when I check the logs the error says "451 4.3.5 Server configuration error". Logs: Mar 16 08:02:37 mail postfix/smtpd[11282]: NOQUEUE: reject: RCPT from mail-bl2nam02on0124.outbound.protection.outlook.com[104.47.38.124]: 451 4.3.5 Server configuration error; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<NAM02-BL2-obe.outbound.protection.outlook.com> Mar 16 11:27:27 mail postfix/smtpd[26084]: NOQUEUE: filter: RCPT from mail-sn1nam01on0121.outbound.protection.outlook.com[104.47.32.121]: <[email protected]>: Sender address triggers FILTER amavis:[127.0.0.1]:10026; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<NAM01-SN1-obe.outbound.protection.outlook.com> I've search on ISPConfig Forums and the internet, but it seems every case has a different error originator. The server is running under Centos 7.4.1708 and ISPConfig version 3.1.11. Attached you will find the main.cf and the master.cf configurations files. Thanks in advance...
