I implemented all the acronyms – DKIM, DMARC, SPF, reverse DNS lookup, SSL in transport, PTR record. I enrolled on Microsoft's JMRP and SNDS, Google postmaster tools. I verified my domain. I got 10/10 on mail-tester.com., –, secured antispam measures, verified my domain, made sure my server is neither breached nor used to relay actual spam, added new servers with supposedly clean IPs from reputable providers, tried all the silver bullets recommended by Hacker News, used kafkaesque request forms to prove legitimity, contacted the admins of some blacklists.