In case your postfix is not able to send mails to gmail accounts due to a IPv6 PTR failure, you are adviced to adhere to IPv4 in Postfix.
edit /etc/postfix/main.cf, and set inet_protocols to ipv4,
You should restart postfix.
edit /etc/postfix/main.cf, and set inet_protocols to ipv4,
inet_protocols = ipv4
You should restart postfix.
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