Delivery Failures

Error Message:

Your message

Subject: {Subject Title}
Sent: {Date] {Time} {Time Zone}

did not reach the following recipient(s):

Variation 1: on {Date] {Time} {Time Zone}
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<{Issuing Server} #5.5.0 smtp;550 Error: Message content rejected>

Variation 2: on {Date] {Time} {Time Zone}
The message contains a content type that is not supported
<{Issuing Server} #5.6.0 smtp;554 5.6.0 Message rejected by content filter (UndisclosedRecipients)>

This non-delivery report provides the relevant information about the email and the error which has occurred.  The {Issuing Server} is not always the server that the error has occurred at but rather the server that issued the error message to the 'Sender'.

The phrase "Error: Message content rejected." and "Message rejected by content filter" indicate the cause.  The errors are self explanatory, the recipients server has rejected the email based on the message content.  This normally indicates that the email contains words, phrases or attachments which have been rejected by the recipients anti-spam system.  The server may have legitimately blocked the email due to its content, blocked the email based on an poorly created anti-spam rule or indicate a significant problem with the anti-spam system.

Conclusion & Action Required:
The sender should contact the recipient to inform them of the issue, if the sender does not believe that the email contains anything which may be considered as a commonly used spam or virus phrase.

The recipient should contact their service provider to enquire as to the cause of the error.

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