What is a “shadow ban” and how does it appear?

A shadow ban (or silent filtering) occurs when messages are accepted but consistently routed to spam without explicit rejection.

How shadow bans work:

Messages are accepted during SMTP transaction (no bounce)

Delivery appears successful in your sending tools

Messages route directly to spam folder

Recipients never see the message in their inbox

No explicit error or notification to sender

Detection signals:

Open and reply rates drop dramatically

Seed tests show consistent spam placement

Recipients report finding messages in spam

Metrics diverge from historical patterns

No bounces despite apparent non-delivery

Why shadow bans happen:

Accumulated reputation damage

Pattern matching to spam behaviors

Low engagement history for your domain

Content or link patterns matching spam

Response:

Confirm with seed testing across providers

Reduce volume significantly

Focus on highest-engagement recipients only

Investigate and address reputation issues

May need extended recovery period

Shadow bans are particularly dangerous because they're invisible without active testing. The ship appears to sail smoothly while cargo never reaches port.