How to fix an invalid email parameter
SES rejected from, to, subject, or headers. What to change before you retry.
You got Invalid email parameter. One field in the send was rejected (from, to, subject, or headers). This is a permanent reject for that attempt — fix the value, then send again.
What to change
- Open the campaign, workflow email, or transactional payload from the notification.
- Check, in order:
- From — must be
name@your-verified-domain. No shared/test domain if that identity is gone. No spaces, angle-bracket typos, or unquoted display names that break the address.
- To — a real mailbox. Role accounts are fine; empty/malformed addresses are not.
- Subject — present. Extreme header injection (raw newlines) will fail.
- Reply-To / custom headers — valid emails only.
- If the From domain is unverified, verify it first.
- Retry the send. Do not keep retrying the same broken From.