> Date: Tuesday, December 08, 2020 11:35:30 +0100 > From: Rene Veerman <rene.veerman.netherlands@xxxxxxxxx> > > i've been at this for a few days now, but keep on getting stuck.. > > while it may be due to my debugging efforts, i can't even get > Thunderbird to send email through that postfix server of mine at > the moment, it delivers the following bounce messages, with a link > that's completely unhelpful :( > > This is the mail system at host smtp.nicer.app. > > I'm sorry to have to inform you that your message could not > be delivered to one or more recipients. It's attached below. > > . . . > > The mail system > <rene.veerman.netherlands@xxxxxxxxx> > <rene.veerman.netherlands@xxxxxxxxx>: host > gmail-smtp-in.l.google.com[2a00:1450:4013:c03::1b] said: > 550-5.7.1 [2001:980:ed77:1:d565:64ae:934a:c18d] Our system > has detected that 550-5.7.1 this message does not meet > IPv6 sending guidelines regarding PTR 550-5.7.1 records > and authentication. Please review 550-5.7.1 > https://support.google.com/mail/?p=IPv6AuthError for more > information 550 5.7.1 . bt17si3147299edb.469 - gsmtp > (in reply to end of DATA command) > Your message is being rejected by google because you don't have a matching PTR record: message does not meet IPv6 sending guidelines regarding PTR 550-5.7.1 records See the: Follow recommended IP practices Verify the sending server PTR record section of the document they reference for specific details, but you should follow the guidelines on SPF/DKIM/DMARC in the following section too: Make sure your messages are authenticated In general, and especially when sending to google via IPv6, your mail configuration (server and dns records) needs to be fully standards compliant.
