What is a bounce message (NDR)? A Clear Guide

A bounce message (non-delivery report) is the automated reply explaining why an email failed. Reading the SMTP code in it tells you exactly what to fix.

Why it matters

Getting a bounce message (NDR) right keeps you compliant and lands more mail in the inbox. See the deliverability checklist.

How Rainmail helps

Rainmail sends from your own domain on a dedicated, isolated IP with SPF, DKIM, DMARC, reverse-DNS and managed warm-up handled for you, plus an AI watching list health and deliverability — and it welcomes senders SES, SendGrid and Mailchimp reject, from $8. Run the free checker or see plans.