Postfix: Host not found, try again
If you configured Postfix to relay all outgoing mail through a smarthost and that host does not have an MX record — or does not have one anymore — the queue starts filling up and the log fills with deferrals: Jul 14 12:45:39 myhostname postfix/smtp[2349]: 74FBF30501: to=<recipient@example.org> relay=none, delay=3944, status=deferred (Name service error for name=smtp.example.com type=MX: Host not found, try again) The Postfix FAQ is right about the cause, which still leaves the question of what to do about it.
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