Thanks for the info about your mail. I'm using SPF and DKIM too, I don't see how DMARC would help deliverability so I haven't tried that yet. I've verified my d

Thanks for the info about your mail. I'm using SPF and DKIM too, I don't see how DMARC would help deliverability so I haven't tried that yet. I've verified my domains (including the reverse name(s) of my server's IPs) with postmaster.google.com to no avail (and I'm not sending enough mail to get the actual tools enabled). Interesting that you think you could solve it that way, perhaps you're sending more mail, or perhaps M$/Google/AOL are interchanging info and it only helps when going through all of their tools, or perhaps you've sent enough mail that what actually helped was people marking mail as ham, or perhaps you're in a block that's tainted less. My strategy remains to try another IP block. I might also try disabling IPv6 (although IIRC it delivers to Google over IPv4?).