SMTP 354 Start Mail Input vs 556 Domain Does Not Accept Mail
SMTP 354 (Start Mail Input) is a 3xx Positive Intermediate response, while 556 (Domain Does Not Accept Mail) is a 5xx Permanent Negative response. 354 indicates that the server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF). In contrast, 556 means that the destination domain does not accept mail and no forwarding address is available. The domain's DNS configuration (null MX record) explicitly indicates it does not receive email.
الوصف
The server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
متى تراه
After sending the DATA command. The server is now waiting for you to type or stream the email message, ending with a dot on its own line.
كيفية الإصلاح
Send your message content followed by a line with just a period (.) to signal the end. If you get an error after this, check that your message does not contain a bare period on a line by itself within the body.
الوصف
The destination domain does not accept mail and no forwarding address is available. The domain's DNS configuration (null MX record) explicitly indicates it does not receive email.
متى تراه
When sending to a domain that has published a null MX record (RFC 7505) in DNS, explicitly declaring that it does not accept any email messages.
كيفية الإصلاح
Verify the domain's MX records — a null MX (priority 0, empty host) means the domain intentionally rejects all mail. Contact the recipient through an alternative channel.
الفروق الرئيسية
354 is a 3xx Positive Intermediate response, while 556 is a 5xx Permanent Negative response.
SMTP 354: The server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
SMTP 556: The destination domain does not accept mail and no forwarding address is available. The domain's DNS configuration (null MX record) explicitly indicates it does not receive email.
You encounter 354 when after sending the DATA command. The server is now waiting for you to type or stream the email message, ending with a dot on its own line.
You encounter 556 when when sending to a domain that has published a null MX record (RFC 7505) in DNS, explicitly declaring that it does not accept any email messages.
متى تستخدم أيًا منهما
For 354 (Start Mail Input): Send your message content followed by a line with just a period (.) to signal the end. If you get an error after this, check that your message does not contain a bare period on a line by itself within the body. For 556 (Domain Does Not Accept Mail): Verify the domain's MX records — a null MX (priority 0, empty host) means the domain intentionally rejects all mail. Contact the recipient through an alternative channel.