Fix · Forms and email

"Delivery failed" message came back (bounce)

What you may see

I get a mail delivery failure notice

Most likely cause

The receiving server refused the message: the address does not exist, the mailbox is full, or the sender was rejected.

Check first (about two minutes)

Read the code in the notice (for example 5.1.1 = address does not exist).

The fix prompt

What you type here never leaves your browser. The search runs on this page, and nothing is sent to a server or to an AI.

The exact error or what you see

What you did before it happened

Kept only in this browser, on this device. Keys and passwords are removed before anything is saved.

Prompt language

You are a careful senior engineer who knows website forms and email sending, and explains them to people who are not developers. I am not a developer, so explain every step in plain words and tell me exactly which button, menu or command you mean. If you are not sure about something, say so; do not guess.

THE PROBLEM
"Delivery failed" message came back (bounce)

THE EXACT ERROR OR WHAT I SEE
[paste the exact error here]

WHAT I DID BEFORE IT HAPPENED
[write in a few words what you did before it happened]

MOST LIKELY CAUSE
The receiving server refused the message: the address does not exist, the mailbox is full, or the sender was rejected.

DO THESE STEPS, IN THIS ORDER
1. Explain the code and the reason in plain words.
2. For a wrong address, fix the form (validate email format; ask to confirm) and stop sending to that address.
3. For sender rejection, check the authentication entry.
Stop and tell me if what you see does not match a step. Do not skip ahead.

CHECK THAT IT WORKED
- Future messages to the same address are not attempted, and valid addresses receive mail.
Tell me exactly what I should see on the screen when it works.

DO NOT CHANGE
- Do not keep resending to a bounced address.
- Anything I did not ask about: the design, the text, other pages, other settings or the data.
- Do not delete files, data or branches, do not reset or force-push, and do not rewrite history, unless you first show me exactly what would be lost and I say yes.
- Do not paste, print or ask me to paste a password or secret key into this chat. If one is needed, tell me which settings page of the right service to store it in.

WHEN YOU FINISH
Explain in simple words what you changed (file by file or setting by setting), why you changed it, and how I can undo it.

Paste it into Claude, ChatGPT, Gemini or Cursor, then follow what it says.

After you tried it, did it work?

Steps

Explain the code and the reason in plain words.
For a wrong address, fix the form (validate email format; ask to confirm) and stop sending to that address.
For sender rejection, check the authentication entry.

Do not do this

Do not ignore many bounces: they hurt your reputation.
Do not keep resending to a bounced address.

Fix it My emails land in spam

Try another entry