Remote Server returned '554 5.6.0 Invalid message content (Transport Rules Agent)

jibin chacko 21 Reputation points
2022-10-26T17:31:28.207+00:00

Hi ,
When we are sending an invoice PDF file the mail is being deferred by exchange and not delivered to internal and external users.
the PDf file is clean but this is happening with a particular pdf only.
Sender will receive an NDR with Remote Server returned '554 5.6.0 Invalid message content (Transport Rules Agent)

what could be the reason

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
3,868 questions
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,009 questions
Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
1,673 questions
0 comments

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. LilyLi2-MSFT 1,976 Reputation points
    2022-10-27T03:23:40.97+00:00

    Hi @jibin chacko ，

    I noticed that your file format is PDF. Do you also receive this error if you send attachments in other formats, such as .xlsx files or .docx files?

    If you are using O365, please see this article: invalid-message-ndr
    This issue may occur if the following conditions are true:

    • A transport rule is set up that has the Defer the message if rule processing doesn't complete option enabled.
    • During text extraction, the scanning process timed out when inspecting the attachment.

    It is recommended that senders try the following steps:

    • Password-protect the message before you send it.
    • Disable the Defer the message if rule processing doesn't complete option in the transport rule.

    If the suggestions above don't work, please run a message trace, and provide full NDR reports (please be careful to hide your private information).

    If an Answer is helpful, please click "Accept Answer" and upvote it.
    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.