SMTP Error 455

What causes this error and solutions

SuprSend provides APIs and components for you to create notification workflows that drive collaboration & actions from your users - ensuring higher product adoption.

TABLE OF CONTENTS

SMTP Error 455 is a permanent or "5xx" error code returned by a mail server, indicating the rejection of an incoming email message due to specific policy violations or other reasons. Unlike transient errors, SMTP Error 455 signifies a persistent issue that requires addressing the underlying problem.

SMTP Error 455 Examples:

  • "455 5.7.1 Content blocked due to policy violations. Email flagged as spam."
  • "455 5.1.0 Sender's domain blacklisted for abusive behavior. Contact administrator for removal."
  • "455 5.5.2 Invalid recipient address recipient@example.com. Check recipient details."

What's Causing This Error?

SMTP Error 455 can stem from various reasons, including:

  • Content policy violations: The email message contains content that breaches the recipient server's policies, such as spam, malware, or prohibited file types.
  • Sender reputation issues: The sender's email address or domain has a poor reputation, possibly due to previous policy violations or spammy behavior.
  • Invalid recipient address: 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.

How to Resolve SMTP Error 455?

To address SMTP Error 455, follow these steps:

  • Review email content: Ensure that the email message content complies with the recipient server's policies. Remove or modify any content that may be flagged as spam or malicious.
  • Improve sender reputation: Address any issues related to the sender's reputation by adhering to email best practices and policies. Avoid sending spam or engaging in spammy behavior.
  • Verify recipient address: Ensure that the recipient's email address is spelled correctly, is complete, and corresponds to a valid email account or mailbox.

Say Goodbye to all SMTP Errors in Development

SuprSend eliminates the need to build and configure email servers from scratch, ensuring you steer clear of SMTP errors. Here's how SuprSend would work for your application, building a reliable notification system.
Dashboard mockup
Written by:
Sanjeev Kumar
Engineering, SuprSend

Say Goodbye to all SMTP Errors in Development

SuprSend eliminates the need to build and configure email servers from scratch, ensuring you steer clear of SMTP errors. Here's how SuprSend would work for your application, building a reliable notification system.
Dashboard mockup

More to explore

Implement a powerful stack for your notifications

By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. View our Privacy Policy for more information.