Hi and happy new year 
,
I setup smtp notification with google smtp server (smtp.gmail.com) but notifications are not send via email.
The sendmail logs show this error message : "dsn=4.0.0, stat=Deferred: 421 4.7.0 Try again later, closing connection".
This is the full log (email adresses are hidding). you can see in log that sendmail use "smtp-relay.gmail.com" instead of "smtp.gmail.com".
2023-01-01T15:57:39.604063+00:00 localhost sendmail[13787]: My unqualified host name (localhost) unknown; sleeping for retry
2023-01-01T15:58:39.553071+00:00 localhost sendmail[13789]: unable to qualify my own domain name (localhost) -- using short name
2023-01-01T15:58:39.560239+00:00 localhost sendmail[13789]: 301FwdM5013789: from=supxxxx@xxxxxx.com, size=977, class=0, nrcpts=1, msgid=<202301011558.301FwdM5013789@localhost>, relay=root@localhost
2023-01-01T15:58:39.566312+00:00 localhost sendmail[13789]: STARTTLS=client, relay=[127.0.0.1], version=TLSv1.2, verify=FAIL, cipher=AES256-GCM-SHA384, bits=256/256
2023-01-01T15:58:39.566649+00:00 localhost sendmail[15881]: STARTTLS=server, relay=localhost [127.0.0.1], version=TLSv1.2, verify=NO, cipher=AES256-GCM-SHA384, bits=256/256
2023-01-01T15:58:39.569658+00:00 localhost sendmail[15881]: 301Fwdkq015881: from=<supxxxx@xxxxxx.com>, size=1182, class=0, nrcpts=1, msgid=<202301011558.301FwdM5013789@localhost>, proto=ESMTPS, daemon=MTA, relay=localhost [127.0.0.1]
2023-01-01T15:58:39.575882+00:00 localhost sendmail[13789]: 301FwdM5013789: to=mxxxxxxx@xxxxxxx.com, ctladdr=supxxxx@xxxxxx.com (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30977, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (301Fwdkq015881 Message accepted for delivery)
2023-01-01T15:58:39.604932+00:00 localhost sendmail[13787]: unable to qualify my own domain name (localhost) -- using short name
2023-01-01T15:58:39.609965+00:00 localhost sendmail[13787]: 301FwdrM013787: from=supxxxx@xxxxxx.com, size=977, class=0, nrcpts=1, msgid=<202301011558.301FwdrM013787@localhost>, relay=root@localhost
2023-01-01T15:58:39.616183+00:00 localhost sendmail[13787]: STARTTLS=client, relay=[127.0.0.1], version=TLSv1.2, verify=FAIL, cipher=AES256-GCM-SHA384, bits=256/256
2023-01-01T15:58:39.616399+00:00 localhost sendmail[15884]: STARTTLS=server, relay=localhost [127.0.0.1], version=TLSv1.2, verify=NO, cipher=AES256-GCM-SHA384, bits=256/256
2023-01-01T15:58:39.621366+00:00 localhost sendmail[15884]: 301Fwdh6015884: from=<supxxxx@xxxxxx.com>, size=1182, class=0, nrcpts=1, msgid=<202301011558.301FwdrM013787@localhost>, proto=ESMTPS, daemon=MTA, relay=localhost [127.0.0.1]
2023-01-01T15:58:39.628186+00:00 localhost sendmail[13787]: 301FwdrM013787: to=mxxxxxxx@xxxxxxx.com, ctladdr=supxxxx@xxxxxx.com (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30977, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (301Fwdh6015884 Message accepted for delivery)
2023-01-01T15:58:39.753662+00:00 localhost sendmail[15883]: 301Fwdkq015881: to=<mxxxxxxx@xxxxxxx.com>, delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=121182, relay=smtp-relay.gmail.com. [74.125.140.28], dsn=4.0.0, stat=Deferred: 421 4.7.0 Try again later, closing connection. (EHLO) j10-20020a05600c190a00b003d978e430fesm1405459wmq.42 - gsmtp
2023-01-01T15:58:39.759379+00:00 localhost sendmail[15886]: 301Fwdh6015884: to=<mxxxxxxx@xxxxxxx.com>, delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=121182, relay=smtp-relay.gmail.com. [74.125.140.28], dsn=4.0.0, stat=Deferred: 421 4.7.0 Try again later, closing connection. (EHLO) n14-20020adf8b0e000000b002416f2e74d5sm1067667wra.87 - gsmtp
2023-01-01T16:02:59.567131+00:00 localhost sendmail[18900]: My unqualified host name (localhost) unknown; sleeping for retry
