Sorry, I have a non-delivery report :
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<
[email protected]>: host
gmail-smtp-in.l.google.com[2a00:1450:400c:c07::1b] said: 550-5.7.1
[2001:41d0:1:7e05::] 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
Bulk Senders Guidelines - Gmail Help for more information 550
5.7.1 . h144-v6si825663wme.116 - gsmtp (in reply to end of DATA command)
And there is the logs :