We recently moved our DNS to Cloudflare, got all the DNS records set up, and things worked great. But we soon discovered that our site’s contact forms and semdmail in general (we use php) were broken. The site is on a dedicated server with its dedicated IPv4 and IPv6 addresses. After some investigation, we discovered that sendmail on the server is returning the following error message from Google (we use Google’s G Suite for our email):
“Our system has detected that this message does not meet IPv6 sending guidelines regarding PTR records and authentication. Please review https://support.google.com/mail/?p=IPv6AuthError for more information.”
The site needs to be accessible both via IPv4 and IPv6. When we created the DNS records on Cloudflare, we added one A record for the IPv4 and one AAAA record for IPv6 - both proxied.
When we turned the proxies off, the email service on the sever went back to normal and worked fine.
Have we missed any setting as we would like to have the advantage of the site being proxied?
Any insight will be much appreciated.