My personal Hotmail account cannot send emails

Open an Outlook.com support request from the affected Hotmail account and ask for an account-specific review of the web-mail outbound filtering that returns 550 5.7.520 AS(4810).

Start the investigation

1. Sign in to Outlook.com using the affected Hotmail account.
2. Select Help on the top menu, then Help.
3. Enter:

   Outlook.com web sending rejected with 550 5.7.520 AS(4810)

4. Review the displayed result, then return to the main Help pane if necessary.
5. Scroll to Still need help? and select Yes to submit an email support request. Microsoft notes that the back arrow may be required to return to the pane where Still need help? appears.^1^

This is the consumer Outlook.com support route. A personal Hotmail mailbox is not escalated through the Microsoft 365 Admin Center.

Include a precise evidence package

Paste the following into the request, replacing the bracketed values:

Product: Personal Hotmail mailbox using Outlook.com
Error: 550 5.7.520 AS(4810)
First observed: [date, time, and time zone]
Latest occurrence: [date, time, and time zone]
Web reproduction: Immediate rejection in both Safari and Chrome
Private browsing: Same result
Minimal-message test: Plain text, one recipient, no attachment, link, image, or signature; same result
Control test: The same mailbox can send successfully through [email app and platform]
Recipients affected: [all tested recipients, or list the recipient domains]
Request: Please perform an account-specific investigation of the Outlook.com web-mail outbound filtering decision for AS(4810). Because sending succeeds through an email app but fails through Outlook.com, please compare the web and app submission paths and escalate to the Outlook.com email-delivery team if a service-side review is required.

Attach or paste:

• The complete rejection or non-delivery report, not only the numeric code.
• The failed message’s date, exact time, time zone, recipient domain, and subject.
• A screenshot of the Outlook.com error with personal addresses obscured.
• Safari and Chrome versions and the operating-system version.
• The email app/platform that succeeds and a successful-send timestamp for comparison.
• Whether every recipient fails or only particular domains.

A closely matching Microsoft Q&A resolution recommends an account-specific review and explicitly says not to repeat browser/device and plain-text troubleshooting once those tests have already been completed.^2^

If Contact Support does not appear

• Use the back arrow in the Help pane and try the search again; Still need help? → Yes appears at the bottom of the self-help results.
• If the Outlook.com Help control fails, use Microsoft’s general personal-account support page and describe the same error and reproduction details.^3^
• Ensure the mailbox has room for support replies. Microsoft states that support cannot reply when the mailbox is full.^1^

Do not publish the email address, full message headers, recovery information, or case correspondence in a public Q&A thread. Community moderators can guide escalation, but they might not be able to inspect private account restrictions.^2^

The IP delisting portal is not the appropriate first route here: Microsoft documents that process for external senders receiving 5.7.511, whereas this case is a personal Hotmail mailbox returning 5.7.520 AS(4810) during Outlook.com web submission.

References

1. How to get support for Outlook.com | Microsoft Support
2. I can receive emails but cannot send. Error 550 5.7.520 AS(4810) - Microsoft Q&A
3. Contact Microsoft customer support | Microsoft Support