Hi, I have installed ispconfig3 , but when i am trying to send email to gmail. I got message below, please help. I have created dns for apptob.tobiku.com , but it is not working also. : host gmail-smtp-in.l.google.com[2404:6800:4003:c03::1a] said: 550-5.7.1 [2400:8901::f03c:93ff:fedc:918c] Gmail has detected that this message 550-5.7.1 does not meet IPv6 sending guidelines regarding PTR records and 550-5.7.1 authentication. For more information, go to 550 5.7.1 https://support.google.com/mail/?p=IPv6AuthError t42-20020a056a0013aa00b006d990db77besi5017574pfg.135 - gsmtp (in reply to end of DATA command) Reporting-MTA: dns; apptob.tobiku.com X-Postfix-Queue-ID: DD74C600D4
You missed adding an IPv6 PTR record. This is normally not done in ISPConfig, it's done by your data center or in the configuration console of your data center. And the other point is that the email client you used might not be using SMTP authentication to connect to the email server.
