SMTP error 500 is a generic permanent error code returned by a mail server, indicating a failure in email delivery. This error code doesn't specify the exact reason for the failure but indicates a fundamental issue that prevented the server from accepting or delivering the email. SMTP error 500 falls under the "5xx" class of errors, denoting permanent failures.

SMTP Error 500 Examples:

• "500 5.5.1 Syntax error in email message. Check message format."
• "500 5.7.1 Content blocked due to policy violations. Email flagged as spam."
• "500 5.3.4 Authentication failed. Please check your login credentials."
• "500 5.4.3 DNS configuration error. Verify DNS settings for sender@example.com."

What's Causing This Error?

SMTP error 500 can be triggered by various issues, including:

• Syntax errors: The email message or SMTP commands may contain syntax errors that make it impossible for the server to process the message.
• Policy violations: The email message might violate the recipient server's policies, such as sending spam, containing malicious content, or exceeding size limits.
• Authentication issues: Incorrect login credentials or lack of proper authentication may result in SMTP error 500 when trying to send emails.
• DNS issues: Problems with DNS (Domain Name System) configuration or resolution can affect the delivery of emails.

How to fix SMTP Error 500?

To resolve SMTP error 500, follow these steps:

• Review email content: Carefully inspect the content of the email message to ensure it complies with the recipient server's policies. Remove or modify any content that may be flagged as spam, malicious, or in violation of policies.
• Check for syntax errors: Ensure that the email message and SMTP commands do not contain syntax errors. Incorrectly placed commas, periods, or other punctuation can trigger errors.
• Verify authentication: If authentication is required, confirm that the login credentials are correct and that the email client or server is properly configured for authentication.
• Address DNS issues: If DNS problems are suspected, ensure that the DNS settings for the sender's domain and the recipient's domain are correctly configured.