Hello, I have configured postfix, dovecot with ssl from letsnecrypt. It works fine, but gets rejected when sending mails to gmail, with following rejection message:
Reporting-MTA: dns; xxx.com X-Postfix-Queue-ID: 0350A19652F X-Postfix-Sender: rfc822; x...@xxx.com Arrival-Date: Mon, 13 Jun 2022 08:45:06 +0000 (UTC) Final-Recipient: rfc822; x...@gmail.com Original-Recipient: rfc822;x...@gmail.com Action: failed Status: 5.7.1 Remote-MTA: dns; aspmx.l.google.com Diagnostic-Code: smtp; 550-5.7.1 [2a01:4f9:c012:7b57::1] Our system has detected that this message does 550-5.7.1 not meet IPv6 sending guidelines regarding PTR records and 550-5.7.1 authentication. Please review 550-5.7.1 https://support.google.com/mail/?p=IPv6AuthError for more information 550 5.7.1 . x8-20020a7bc208000000b0038ffbcf8a3bsi7451922wmi.106 – gsmtp Please suggest how to resolve this. Initially smtp_tls_security_level = may, was verify and sending emails were getting rejected, then we made it may. After that we for rejection emails from google. Regards, Ranjan