Emails bouncing back

Question

When I send an email with a picture attached, it is returned to me as undeliverable..The error message I get is: "Diagnostic information for administrators:

Generating server: SN4P221MB0810.NAMP221.PROD.OUTLOOK.COM

Remote server returned '554 5.7.0 < #5.7.520 smtp;550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)>'

This happens even if I send a message with a picture in it to myself.

What is needed to correct this problem?

Answer 1

,

Due to a lot of spam abuse, Microsoft has placed certain restrictions and imposed a daily limit on emails, especially if the email was recently created.

Sending limits in Outlook.com

https://support.microsoft.com/outlook/sending-limits-in-outlook-com

Also,

Do you have a signature in your Email? If so, please remove it temporarily and verify.

Second, try switching the Email to Plain Text instead of HTML as a troubleshooting step.

The setting is below:

Open The Gear icon > Settings.

Go to Mail > Compose and Reply.

Change the message format to Plain text.

User's image

If nothing works, file the form at https://sender.office.com and the restrictions will be lifted.

A friendly reminder that this is a user-to-user forum where users help other users.

Experts or Advisors participating here cannot make changes to Microsoft services or access internal systems and can only provide technical guidance, irrespective of Microsoft's Policy decisions.

I hope this information helps. If you have any more questions, don't hesitate to reach out. Wishing you good luck!

Answer 2

The error indicates the message is being flagged as spam because of its content. Since it happens when sending a message with a picture attachment, start by isolating what in the message is triggering the filter:

1. Sign in to Outlook on the web.
2. Open the message and remove anything that looks risky, especially:
   • the picture attachment
   • links in the message
   • shortened links
   • repeated text
3. Send a plain-text test message with no attachment to confirm sending works.
4. If that succeeds, add content back step by step until the message is blocked again. That identifies the trigger.

Also check Outlook.com sending conditions that can block or affect delivery:

• If the attachment is larger than 25 MB, Outlook.com cannot send it.
• If a signature is included, remove the signature and resend, because signatures can sometimes affect sending.
• If the message is being resent from a failed-delivery notice, and the original attachment is larger than 10 MB, resend it from Sent Items instead of using Send Again.
• If the file is large, save it to OneDrive and share a link instead.

If the recipient address was auto-completed, remove the cached entry and type the full address again before resending:

1. In the new message, delete the recipient from the To box.
2. Start typing the address until it appears in Auto-Complete.
3. Select it with the Down Arrow key and delete it.
4. Type the full address manually and send again.

If the address is correct and the message still generates a non-delivery report, use Sender Support in Outlook.com.

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References:

• emails undeliverable - Microsoft Q&A Remote server returned '554 5.7.0 < #5.7.520 smtp;550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)>'
• Can't send or receive email in Outlook.com
• Failed delivery messages from the postmaster at outlook.com, microsoft.com, or service.microsoft.com