SMTP Error 452 is a transient or "4xx" error code returned by a mail server, indicating temporary resource constraints or limits being exceeded, preventing the acceptance or processing of incoming email messages at that moment. Unlike permanent errors, SMTP Error 452 suggests a temporary issue that may resolve in the future.

What are the cases covered in SMTP Error 452?

SMTP Error 452 in phpmailer Instances & Examples:

• Case 1: "452 4.3.2 Temporary failure, please try again later."
• Case 2: "452 4.7.1 Greylisted - Try again in 15 minutes."
• Case 3: "452 4.4.3 Server resources exhausted, try again in a few minutes."

What’s Causing This SMTP Error 452 In Your Servers? (in pointers)

SMTP 452 error in phpmailer can occur due to:

• Server overload: The mail server is currently processing a high volume of incoming email traffic, temporarily rejecting new connections or delaying email delivery to manage the load effectively.
• Resource constraints: Limited server resources (e.g., CPU, memory, disk space) restrict new email deliveries temporarily to manage resource allocation efficiently.
• Greylisting: Some mail servers employ greylisting as an anti-spam technique, initially rejecting emails from unknown senders with a 452 error. Legitimate senders retry delivery after a delay, and the email is accepted.

How to Resolve SMTP Error 452 - Step-by-Step Solution

To address this email smtp error 452 in Jenkins servers, follow these steps:

• Wait and retry: Since SMTP Error 452 is temporary, wait and retry sending the email later. The receiving server may resolve its temporary constraints, allowing successful delivery.
• Check for greylisting: If suspecting greylisting, waiting and retrying the email should resolve the issue upon acceptance by the receiving server.
• Investigate resource constraints: If you have control over the receiving server, investigate and address any resource constraints causing the error.