Oftentimes, absolutely no one knows why your email got blocked or bulked, but that isn’t necessarily a problem.
The answer to the question, “Why was my email blocked?” has changed in the last 10 years. I’ve heard this question many times. It’s the first question anyone asks when they find out they have a deliverability issue. A decade ago, the answer was usually pretty straightforward. Blocklists, spamtraps, complaints, bounces, spam keywords—whichever the specific cause—it was generally fairly easy to figure out.
Today, though, the honest answer in many cases is, “I don’t know.”
This isn’t a popular answer. It’s not one that most deliverability people are comfortable giving, and it’s certainly not one clients want to hear, so it’s not usually the answer you’ll be given. Instead, possible, plausible, and likely causes are given. The truth is that not even the ISP’s own staff actually knows for sure why a given email was blocked.
A little while back, I had the pleasure of attending...