Error: 4.4.7 Non-Delivery Message

Problem: When you send an email, you receive a 4.4.7 error message: Non-Delivery Receipt (NDR) message

Solution: A 4.4.7 NDR message usually indicates a problem on the receiving server; check the validity of the recipient's address. You can also perform an MX lookup on the receiving domain to determine if the receiving server is configured to receive messages correctly.

A 4.4.7 NDR message can also indicate that a message header limit has been reached on a remote server or that some other protocol timeout has occurred while communicating with the remote server. It may be necessary to reduce the number of recipients in the header of the message for the host to which you are receiving this error. If you then resend the message, it is placed in the queue again, and if the receiving server is up, the message is delivered.

An example of the typical bounce-back NDR message is shown below:

-----Original Message-----
From: System Administrator
Sent: DateTime
To: 'Recipients_Name'
Subject: Undeliverable: Subject_Of_Original_Message
Your message did not reach some or all of the intended recipients.
Subject: Subject_Of_Original_Message
Sent: DateTime
The following recipient(s) could not be reached:
'Recipients_Name' on 3DateTime Could not deliver the message in the time limit specified. Please retry or contact your administrator.
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