Comment 8 for bug 1721803

The MTA logs indicate that Gmail is deferring/rejecting some messages, but Google is notoriously vague about why. Rejections from some other non-Google MTAs note that the server has become listed in the Mailspike blacklist, and per separate bug 1745512 I've put in a delisting request there. Some rejections also claim the server is covered by a Spamhaus PBL entry but their lookup form disagrees as of today at least (perhaps some MTAs are relying on very stale/cached results?).