build1 publisher
Suppressing on the three-digit code converts a policy refusal into a dead address
In four codebases a dev.to author found bounce handlers that read 5.x.x and stopped, so a receiver's verdict on the sending domain got written down as a dead mailbox. The RFC 3463 subject digit separates the two.
Publishers:dev.to
Reality
- Evidence55
- Adoption
- Insufficient
- Hype gap+12
- Incentives40
- Confidence57