SMTP error 534 is a permanent error (5xx) indicating the recipient server rejected your email due to authentication failure or insufficient credentials. This means your email client or server couldn't provide valid login information (username and password) or lacked the necessary permissions to send the email. This error can occur in applications like phpmailer and jenkins when sending emails.

What are the cases covered in SMTP Error 534?

Common scenarios triggering SMTP Error 534:

1. Incorrect or Incomplete Credentials: Your email client or server provided wrong or missing login details (username/password) during authentication with the recipient server (phpmailer, jenkins).
2. Insufficient Permissions: Your email account lacks the necessary authorization to send emails through the recipient server. Contact the email administrator if needed.
3. Authentication Mechanism Issues: The recipient server requires specific authentication methods (e.g., SMTP-AUTH) that are not used or configured correctly.
4. Suspended or Locked Account: Your email account with the recipient server might be suspended, locked, or restricted from sending emails.

What’s Causing This SMTP Error 534 In Your Servers?

Potential causes of SMTP Error 534:

• Incorrect Credentials: Double-check that the username and password for SMTP authentication are accurate, complete, and belong to a valid sender account (phpmailer, jenkins).
• Insufficient Permissions: Verify if your email account has the required permissions to send emails through the recipient server. Contact the email administrator if needed.
• Incorrect Authentication Configuration: If the recipient server requires specific authentication methods, configure your email client or server to use the appropriate mechanisms like SMTP-AUTH.
• Account Issues: If your email account is suspended, locked, or restricted, contact the email administrator or hosting provider to resolve the account-related issues.

How to Resolve SMTP Error 534 - Step-by-Step Solution

1. Verify Credentials: Ensure the provided username and password are correct, complete, and belong to a valid sender account (phpmailer, jenkins).
2. Check Permissions: Confirm your account has the necessary permissions to send emails through the recipient server. Contact the email administrator if needed.
3. Configure Authentication: If required, configure your email client or server to use the appropriate authentication methods like SMTP-AUTH.
4. Address Account Issues: If your account is suspended, locked, or restricted, contact the email administrator or hosting provider to resolve the situation.

SMTP Error 534 Examples

• "534 5.7.0 Authentication failed. Please check your username and password."
• "534 5.7.3 Insufficient permissions to send email. Contact administrator for access."
• "534 5.7.1 Incorrect authentication mechanism. Use SMTP-AUTH for secure login."
• "534 5.5.0 Account locked. Email sending is temporarily restricted."

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