Reference
Spam Checks on the email detail page
Each outgoing email's detail page lists the spam filter checks that matched and their scores, so you can see why a message was held.
Updated Sep 29, 2026
Open an email in Email API → Emails to find the Spam Checks panel under the deliveries. It lists every rule the spam filter matched, with a description and a score. Filter by Negative (rules that raised the score), Positive (rules that lowered it) or Neutral.
Messages that score 7 or more are held. Use the checks to find what to change, then retry the email. See Spam checks.