Ironic, since Microsoft is the worst (in my experience) at being a giant black hole to emails sent from an otherwise well-configured (SPF, DKIM, DMARC, non-SBL-

Ironic, since Microsoft is the worst (in my experience) at being a giant black hole to emails sent from an otherwise well-configured (SPF, DKIM, DMARC, non-SBL-listed IP, &c) but not major SMTP host.