Paste a delivery failure to identify SMTP and enhanced status codes. Get a practical explanation without sharing the message.
The analyzer recognizes common 4xx and 5xx replies and enhanced status-code categories. Provider-specific diagnostic text remains important.
A 4xx response normally indicates a transient condition; 5xx indicates a permanent failure for that transaction. Neither alone proves that an address will always fail.
Codes such as 5.1.1, 4.2.2 or 5.7.1 describe categories like addressing, mailbox state and policy. The exact provider diagnostic can refine the explanation.
Resolve addressing or authentication errors before retrying. For temporary failures, use your sender’s retry behavior rather than repeatedly sending manually.
No. It interprets the supplied diagnostic. A generic policy rejection or rewritten provider response is not independent proof of mailbox existence.
No. Text is analyzed locally in your browser.