SMTP Error 432 is a transient or "4xx" error code returned by a mail server, indicating a temporary issue during the processing of an email message. This error signals that the server cannot complete the request at the moment, and the sending server should attempt email delivery again later.

What's Causing This SMTP Error 432:

SMTP Error 432 in phpmailer:

1. Server congestion: The mail server is currently handling a high volume of incoming email traffic, causing delays in processing new messages.
2. Rate limiting: The server may impose limits on the number of emails a sender can send within a specific time frame, triggering a 432 error if exceeded.
3. Temporary server issues: Hardware, software, network problems, or other transient issues can lead to SMTP error 432.
4. Greylisting: Some mail servers use greylisting as a spam-fighting technique, initially rejecting emails from unknown senders with a 432 error. Legitimate senders can retry delivery after a delay.

SMTP Error 432 in Jenkins:

1. Server congestion: The mail server in Jenkins is currently handling a high volume of incoming email traffic, leading to processing delays.
2. Rate limiting: Jenkins server may impose limits on the number of emails a sender can send within a specific time frame, resulting in a 432 error if exceeded.
3. Temporary server issues: Hardware, software, network problems, or other transient issues can lead to SMTP error 432.
4. Greylisting: Jenkins mail server may use greylisting as a spam-fighting technique, initially rejecting emails from unknown senders with a 432 error. Legitimate senders can retry delivery after a delay.

How to Resolve SMTP Error 432 - Step-by-Step Solution:

To resolve SMTP Error 432, follow these steps:

1. Wait and Retry: This error is typically temporary, caused by server congestion, rate limiting, or other transient problems. Wait and retry the email delivery later; the receiving server should eventually accept the message.
2. Check for Rate Limits: If sending a high volume of emails, ensure you don't exceed rate limits imposed by the receiving server. If exceeded, consider spreading out email sending over a longer period.
3. Investigate Server Issues: If consistently encountering SMTP error 432 to a specific recipient or domain, contact the recipient's email administrator. It may indicate the recipient's mail server is experiencing issues.

SMTP Error 432 Examples:

• "432 Service temporarily unavailable. Please try again later."
• "432 Rate limit exceeded for sender@example.com. Try again in an hour."
• "432 Greylisted - Retry email delivery in 15 minutes."
• "432 4.3.2 Server experiencing temporary issues. Email delivery delayed."