What is a “shadow ban” and how does it appear?
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Your open rates have fallen off a cliff. No bounces, no errors, your ESP says every message was delivered. But somehow, nobody's reading. What's going on?
You might be shadow banned.
A shadow ban (sometimes called silent filtering) is when a mailbox provider accepts your email at the SMTP level but immediately routes it to spam. The important thing to understand is that "accepted" doesn't mean "delivered to the inbox." Your sending tool sees a success signal. The recipient's spam folder gets another unread message. And you have no idea.
Picture sending a sequence of emails to prospects, watching your open rate drop from 35% to 3% over two weeks, and finding zero bounce errors. That's the classic shadow ban pattern. The numbers lie, and you don't find out until someone checks their spam by accident.
How to spot it
But a few signals tend to cluster together when a shadow ban is happening. Open and reply rates drop sharply while your bounce rate stays flat. Recipients who used to respond have gone quiet. If you run seed tests, you'll see consistent spam folder placement across multiple providers. That last one is the most reliable signal, because anecdotal feedback from recipients can be slow to come back to you.
And the tricky part is separating a shadow ban from just a rough campaign. A bad campaign usually recovers within a send or two. A shadow ban keeps producing spam-folder placements no matter what subject line or content you test.
Why it happens
Mailbox providers like Gmail and Outlook build a reputation profile for your domain over time. When that reputation drops far enough, they stop rejecting your mail outright and just quietly file it away. Common causes include accumulated low engagement, high spam complaint rates, content patterns that match known spam, or sending to too many unresponsive addresses.
What to do about it
Start by confirming with seed testing across multiple providers. If seeds consistently hit spam, it's not a content fluke. Then cut your sending volume significantly and focus only on your most engaged recipients. People who open and click regularly. That concentrated engagement signal is what starts moving the needle back. Recovery usually takes weeks, not days, so don't expect a quick fix.
It's also worth checking whether your domain reputation shows up as damaged in the tools providers publish. If things feel stuck and you're not sure where to start, our SOS hotline is free and we'll help you work through it.
You can also check if your domain or IP is on a blocklist right now, no signup needed.
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