Outlook.com blocks all outgoing emails with 550 5.7.520 AS(4810)

Question

Outlook.com blocks all outgoing emails with 550 5.7.520 AS(4810)

Maria Daniela Ostos Arboleda 0

My personal Hotmail/Outlook.com account is suddenly unable to send any outgoing email.

Every message is rejected with the following error:

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

I have already ruled out message content and the Outlook application:

The issue occurs with brand-new emails containing only a simple word such as “Hello”.

No links, attachments, images, signatures, or forwarded content are included.

The issue also occurs when sending directly from Outlook.com on the web.

I reviewed my Microsoft account's recent sign-in activity and recognize all activity.

I changed my Microsoft account password and signed in again.

After changing the password, I tested again from Outlook.com and received the same AS(4810) rejection.

This appears to be an outbound spam/reputation false positive or sending restriction at the account/service level rather than an issue with the content of an individual message.

Could a Microsoft moderator please advise how to have the outbound AS(4810) restriction reviewed/escalated by the Outlook.com service team? If diagnostic information such as the NDR, correlation ID, timestamps, or Message-ID is required, I can provide it through a private support channel.

Thank you.

0 comments

2 answers

Your answer

Answer 1

Maria Daniela Ostos Arboleda 0

Update: I followed the suggested troubleshooting and added the Gmail recipient to my Outlook.com contacts. I then sent a new simple test message to the saved contact. The message was still rejected with exactly the same error:

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

This confirms that the issue persists regardless of message content and whether the recipient is saved as a contact.

Could this please be escalated for a service-side review of the outbound sending restriction/reputation on my Outlook.com account?

I can provide the complete NDR, Message-ID and correlation ID privately if required.

Hornblower409 13,020 Reputation points

2026-08-22T14:30:01.28+00:00
@Maria Daniela Ostos Arboleda said

Could this please be escalated for a service-side review of the outbound sending restriction/reputation on my Outlook.com account?

Microsoft Support does not monitor this forum. You will have to initiate the support process using a standard channel. For a personal hotmail.com account, that would be on-line Chat.

Logon to https://outlook.live.com/

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

Answer 2

For an Outlook.com personal account, the supported self-service path is to use Outlook.com support.

The issue has already been isolated beyond message content and beyond the Outlook client:

Testing in Outlook.com on the web rules out the local Outlook app.
A plain message with only simple text rules out common content triggers such as links, attachments, images, signatures, or formatting.
Since the rejection is still returned after the password change, the next step is service-side review through Outlook.com support.

Use this support path:

In Outlook.com, select Help on the menu bar.
Enter the issue in the help pane.
If the self-help does not resolve it, scroll to Still need help? and select Yes.
If that still does not work or sign-in is affected, use the Outlook.com support entry point provided in the support article.

When submitting the case, include the full non-delivery report and the exact error:

550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)
date and time of the failed sends
whether the failure occurs in Outlook.com on the web
confirmation that the test message was plain text only with no links, attachments, or signature

Additional checks supported by Microsoft guidance for Outlook.com sending problems:

Remove any signature and test again, because signatures can affect sending.
Make sure recipients are in Contacts.
Ask the recipient to add the address to their safe senders list.

If the failure is specific to only certain recipients, the recipient side can also be rejecting the message as spam. In that case, a simple plain-text test to another recipient can help confirm whether the problem is global or recipient-specific.