SMTP Error 553:

What does it mean? And How to resolve this error.

Table of content

Error Description

SMTP error 553 is a permanent or "5xx" error code returned by a mail server to indicate that it has rejected an email message due to issues with the recipient's email address or domain. This error signifies that the email message cannot be delivered because of problems with the recipient's information.

What's Causing This Error?

SMTP error 553 can be caused by several reasons, including:

Non-existent recipient: The recipient's email address provided in the "RCPT TO" command or the "To:" field of the email message does not correspond to a valid email account or mailbox.
Invalid recipient domain: The recipient's email domain (e.g., example.com) does not exist, has expired, or has DNS (Domain Name System) issues.
Unauthorized recipient: The recipient's domain or email address is not authorized to receive email from the sender or is blocked by the recipient's server for policy reasons.
Content filtering: The email message's content may contain prohibited content, such as spam, malware, or other violations of the recipient server's policies.

How to fix SMTP Error 553?

Verify recipient's email address: Ensure that the recipient's email address is spelled correctly, is complete, and corresponds to a valid email account or mailbox.
Check recipient domain: Confirm that the recipient's email domain is functioning correctly, does not have DNS issues, and is not experiencing policy-related blocking.
‍Contact recipient administrators: If the recipient's domain is experiencing issues, it may require intervention by the administrators to resolve technical problems or adjust email acceptance policies.
‍Review email content: Check the content of the email message for potential policy violations, such as spammy content or malicious attachments, and ensure it complies with the recipient server's policies.

SMTP Error 553 Examples

Example 1: "553 5.1.1 recipient@example.com: Recipient address does not exist."

Example 2: "553 5.4.5 recipient@example.com: Domain name not found. Check recipient domain."

Example 3: "553 5.7.0 recipient@example.com: Unauthorized recipient. Email blocked due to policy reasons."

Example 4: "553 5.1.2 Content filtering detected prohibited content in the email message. Delivery denied."

SMTP

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