openSUSE admin

Hundreds of emails are being stalled with messages such as the following:

(host alt1.gmail-smtp-in.l.google.com[2a00:1450:4010:c1c::1a] said: 421-4.7.28 Gmail has detected this message exceeded its quota for sending 421-4.7.28 messages with the same Message-ID. To best protect our users, the 421-4.7.28 message has been temporarily rejected. For more information, go to 421 4.7.28  https://support.google.com/mail/answer/188131 a12-20020a05651c010c00b002d8628654d4si436828ljb.544 - gsmtp (in reply to end of DATA command))

The link does not reveal any recent changes to their policy, we already use outbound TLS if supported by the destination server. Difficulties with sending to Google have been a problem for a long time (https://progress.opensuse.org/issues/109025) due to us not offering a "full fledged" email setup, though I do not recall such a large queue. My speculation is that maybe the issue increased with @suse.com switching to Google, since some SUSE employees might be subscribed to openSUSE mailing lists using their @suse.com address. Another issue could be the "recent" increase in spam.