SMTP error 450 is a transient or "4xx" error code returned by a mail server to indicate a temporary issue with the recipient's server that prevented the delivery of an email message. This error suggests that the recipient's server encountered a problem or was temporarily unavailable, causing a delay in email delivery.

What's Causing This Error?

SMTP error 450 is typically caused by temporary issues on the recipient's side, including:

• Server overload: The recipient's mail server may be experiencing high traffic or resource limitations, resulting in a temporary inability to process incoming messages.
• Connection issues: Problems with the network or server infrastructure can lead to temporary delivery failures.
• Message size or content issues: The recipient's server might have restrictions on email size or content, causing email delivery delays.
• Greylisting: Some servers use greylisting as an anti-spam measure, which can delay the delivery of emails from unknown senders until the message is reattempted.

How to Fix SMTP Error 450?

To resolve SMTP Error 450, follow these steps:

• Wait and retry: In most cases, SMTP error 450 is temporary, and the best approach is to wait and resend the email message later.
• Check recipient's server status: You can check if the recipient's server is experiencing issues or downtime by contacting their email administrator or checking their status page if available.
• Review email size and content: If the email message is very large or contains unusual content, consider optimizing it to meet the recipient's server requirements.
• Contact the recipient: If the issue persists or is a recurring problem, you may contact the recipient to inquire about the status of their email server.

SMTP Error 450 Examples

Example 1: "450 4.1.1 Temporary server overload. Try again later."

Example 2: "450 4.3.2 Connection issues encountered. Delivery delayed."

Example 3: "450 4.2.0 Message size exceeds the recipient's limit. Reduce the message size and resend."

Example 4: "450 4.7.0 Greylisting in effect. The message will be retried for delivery."