https://bz.apache.org/SpamAssassin/show_bug.cgi?id=7953
--- Comment #6 from Cian <cian4apachebugzi...@gmail.com> --- Thanks for taking the time to write all that, Bill. I know you were under no obligation to help, so I really appreciate it. You provided lots of possible ways to improve, and I'm going to try all of them (including, if problems persist, trying the mailing list you mentioned). I haven't gone out of my way to use HTML, but I do occasionally use formatting like bold and italics. Perhaps switching to plain text will help. I have always been conscious to avoid empty or too-short subjects, but I'll meditate on whether I have been going too far in the other direction and using too long subjects. Just to clarify (I am sure your advice still holds), I suspect it is not Microsoft's rules per se that are causing my problem. The recipients I fail to reach seem to be using Outlook as a client, but they are typically at companies with sophisticated enough IT departments that I would expect they're managing their solution with close attention. Think government contractors, federal labs, and universities. Loren, in your line of work, cynicism is completely understandable. For what it's worth, I would say about 1/3 of my emails are to people I personally know and have met, 1/3 I have had personal introductions from someone I personally know to someone whose work is relevant to mine, and the remaining third are people listed as contacts on public websites to address people in my exact position. If it were only the third group who were not receiving my emails, it would still be frustrating, but understandable. I had problems with the first group initially, but less as I go on. What's mind-boggling to me is that I'll get a personal introduction to someone relevant, who is CC'd; they'll reply to the person doing the introduction, CC'ing me; and then I'll reply to them but it won't go through. Anyway, thank you both. I was getting nowhere, and even a close personal friend who works in IT didn't have much insight into what I was doing wrong. You have both been very helpful -- You are receiving this mail because: You are the assignee for the bug.