My Hotmail account (******@hotmail.com) is unable to send emails, including individual messages. I am receiving the following error: 550 5.7.520 – Message blocked because it contains content identified as spam. AS(4810). I recently sent job applica

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My Hotmail account (******@hotmail.com) is unable to send emails, including individual messages. I am receiving the following error: 550 5.7.520 – Message blocked because it contains content identified as spam. AS(4810). I recently sent job applica

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My Hotmail account (******@hotmail.com) is unable to send emails, including individual messages.

I am receiving the following error:

550 5.7.520 – Message blocked because it contains content identified as spam. AS(4810).

I recently sent job applications with my CV attached, and outgoing messages are now being rejected.

Please review my account for any outbound sending restrictions or false-positive spam detection and help restore my email-sending capability.

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2 answers

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Answer 1

Hello,

I've seen a surge in reports from other users experiencing the same issue on the forum over the last several days. Unfortunately, Microsoft hasn't publicly acknowledged the problem.

I'm curious if changing the email format would make a difference. Could you try switching from HTML to Plain Text or Rich Text using the instructions below and see if the email goes through?

https://support.microsoft.com/office/change-the-message-format-to-html-rich-text-format-or-plain-text-in-outlook-338a389d-11da-47fe-b693-cf41f792fefa

If the issue persists, please report it directly to Microsoft so the engineering team can investigate.

In Outlook.com, go to Help > Feedback > Report a problem.

Provide as much detail as possible, including screenshots or a screen recording if available.

I also recommend selecting Yes when asked whether you'd like to share diagnostic logs. These logs can help Microsoft's engineering team identify what's causing the problem.

Answer 2

The error 550 5.7.520 – Message blocked because it contains content identified as spam. AS(4810) indicates the message is being flagged as spam by the receiving mail filter, not necessarily that the Outlook.com account is blocked from sending all mail.

Since this started after sending job applications with a CV attached, the most likely trigger is message content, attachments, links, or HTML formatting.

Try this in order:

Send a plain-text test message with:
- no attachment
- no links
- no signature
- a short, simple subject and body
If that sends successfully, the trigger is in the original message content.
If the plain message works, add content back one item at a time:
- first the normal text
- then the signature
- then any links
- then the CV attachment
This isolates what is causing the spam verdict.
If the CV is a PDF, try an alternative:
- share it by OneDrive link instead of attaching it
- compress it into a .zip file
- send the message as plain text instead of rich text/HTML
In Outlook.com, remove the signature temporarily and resend. Signatures can sometimes affect sending.
Verify the account if recently created. New Outlook.com accounts can have a temporary low sending quota until credibility is established.
If a non-delivery receipt continues even after sending a simple message, use Sender Support in Outlook.com.
If the problem happens only with certain recipients, their mail system may be treating the message as spam. In that case, a very simple email with no attachment helps confirm whether the block is content-based.

If the issue is urgent, the safest workaround is to send the CV by OneDrive link or send a minimal plain-text message first and then add content gradually.