I've configured SSMTP on my Raspberry Pi (Pi 4 with latest Raspbian), it appears to mostly be configured correctly however when I run the command
echo -n 'Subject: test\n\nTesting ssmtp' | sendmail -v email@example.com
to send verify the message, I get this response:
050 550-5.7.1 [2a00:23c7:688e:700:ca02:b77b:23b8:ef02] Our system has detected that 050 550-5.7.1 this message does not meet IPv6 sending guidelines regarding PTR 050 550-5.7.1 records and authentication. Please review 050 550-5.7.1 https://support.google.com/mail/?p=IPv6AuthError for more information 050 550 5.7.1 . d7si66897775wrc.231 - gsmtp 050 <firstname.lastname@example.org>... Connecting to local... 050 <email@example.com>... Sent 250 2.0.0 x6TMB1ha004357 Message accepted for delivery
and I don't receive the message (even though one of the lines states 'message accepted for delivery').
Any ideas how I can resolve this? Obviously this is only an internal device on my home network so it doesn't have a domain associated with it as such.
I do have my own domain and everything related to that is redirected to G-suite business so that is a possibility, but I'm hoping to set this up with just the personal Gmail account.
I've used multiple sites for config instructions however this seems to be authoritative: https://wiki.archlinux.org/index.php/SSMTP