MSN account cannot send any emails, error 550 5.7.520 AS(4810)

Question

MSN account cannot send any emails, error 550 5.7.520 AS(4810)

HNP 0

I have used my @msn.com email account for years, but starting October 12, 2026, all outgoing emails are being rejected with this error:

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

My last successful outgoing emails were on October 9. I sent only three short emails that day.

I have tested from both my cellphone and computer. I also sent a plain-text test email with no attachments, links, or signature. All tests failed, including emails to my company address and my personal Yahoo address.

My account can still receive emails normally. Emails sent from Yahoo to both my MSN account and my company's inbox arrive successfully.

Could a Microsoft representative please explain how I can request a review of my MSN account's outgoing email filtering? I do not administer the msn.com domain and cannot change its SPF, DKIM, or DMARC records.

I have the full non-delivery report, including the message ID and filtering correlation ID, available if needed.

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2 answers

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Answer 1

@HNP said

please explain how I can request a review of my MSN account's outgoing email filtering?

This is a user-to-user forum. If you want to engage Microsoft Support, you have to initiate the action:

New Outlook for Windows or Outlook Web - Free In-App Support

Logon to https://outlook.cloud.microsoft/
From the main menu: Help -> ? Help
{This should open the Help side panel}
Search Help -> {Your problem} and press Enter
Still need help? [Yes]
If you get "We're here to help": Tell us your problem -> {Your problem, again} [Get Help]
[Sign In] {Use any Outlook/Microsoft account}
Choose a support option -> Chat with a support agent in your web browser

I have tested from both my cellphone and computer. I also sent a plain-text test email with no attachments, links, or signature. All tests failed

This is not your normal Spam Bounce situation. Either there is something wrong at the account level (Mother Microsoft has marked your account as a hard core Spammer) or the bounce is coming from some unexpected part of the Microsoft Anti-Spam process.

1 -- Do you have any reason to think you account was/is compromised and the Bad Guys are using it to send Spam?

2 -- The most valuable piece of data would be the full Non-Delivery Report you are receiving. Please be sure to redact part of any personal email addresses. A screen shot or the plain text will do.

Answer 2

Request a private mailbox review through Outlook.com’s signed-in Help pane; Microsoft Learn Q&A cannot inspect or remove an outbound filtering restriction on an individual MSN account.

Submit the review request

Sign in to Outlook.com in a web browser using the affected @msn.com account.
Select Help (?) on the top menu.
Enter: All outgoing mail rejected with 550 5.7.520 AS(4810)
Press Return and review the suggested result.
At the bottom of the Help pane, under Still need help?, select Yes to submit an email support request. If that option is not visible, select the Help pane’s back arrow first. This is Microsoft’s documented support route when a personal Outlook.com user can still sign in.^1^

Include the following in the request:

The complete error: 550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)
The date and approximate time of the last successful message and several failed attempts, including time zone
Your full non-delivery report, including the message ID, filtering correlation ID, generating server, and timestamps
That the failure occurs from both phone and computer
That a plain-text message without links, attachments, or a signature also fails
That unrelated recipients at two different providers are affected
That incoming mail still works normally
A request such as:
“Please review this personal Outlook.com/MSN mailbox for an erroneous outbound anti-spam restriction or false-positive filtering verdict.”

Do not post the complete NDR publicly because its headers can contain account and routing information.

What does not apply here

You do not administer msn.com, so changing its SPF, DKIM, or DMARC records is neither available nor an appropriate user-level fix. The Microsoft 365 Admin Center procedures for Restricted entities, message trace, and outbound spam policies apply to organizational Exchange Online administrators—not to a personal MSN mailbox.^2^

The sender.office.com delisting route is intended for administrators of sending servers or domains whose IP addresses are blocked. It is not the primary escalation path for an MSN user whose mail is being submitted through Microsoft’s own consumer service. A closely matching AS(4810) case likewise directs personal-account users to Help (?) → Contact Support when content changes do not resolve the rejection.^3^

Microsoft’s general Outlook.com guidance also directs users who receive an NDR after confirming the recipient address toward its delivery-support process and recognizes spam-filter rejection as a possible NDR category.^4^

Conditional security check

If Sent Items, forwarding settings, or mailbox rules contain activity you did not create, treat that as possible compromise: change the password, scan the devices, remove unauthorized rules, and then report those findings in the support request. If there is no unfamiliar activity, avoid repeatedly sending tests while waiting for support, because additional rejected attempts will not provide much new diagnostic value.

There is no public evidence here confirming an MSN-wide incident for this exact code and date. Because the same minimal message fails across devices and unrelated recipient systems, the useful next step is the private mailbox-level review rather than repeating content, attachment, client, or recipient tests.

References