Outlook.com blocks all outgoing emails with 550 5.7.520 AS(4810) — request review of sending restriction

Question

I am using a personal Hotmail/Outlook.com account that I have used for many years for legitimate badminton training program communications with students and parents.

I can sign in normally and access the mailbox, but I am currently unable to send any email. Every outgoing message is rejected with the following error:

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

This happens even when:

• The message is sent directly from Outlook.com in a web browser.
• There is only one recipient.
• The subject is simply “test.”
• The body contains only “test.”
• There are no links, attachments, payment information, or other unusual content.

The problem has persisted for more than 12 hours.

For background, this Hotmail account has been used for years to communicate with students and parents regarding badminton training programs. From time to time, emails are sent to a mailing list of student parents with program announcements, registration information, schedules, and occasionally tuition or payment instructions.

These are legitimate communications to families associated with the badminton programs, not unsolicited commercial or spam email.

I understand that the pattern of sending messages to multiple parents, particularly messages that sometimes contain registration or payment information, may have triggered Microsoft's automated anti-spam system. However, the account is now unable to send even a simple one-recipient test message.

If an outbound anti-spam or sending restriction has been placed on this account, I would like to request that Microsoft review the account and lift the restriction so it can continue to be used for legitimate badminton program communications.

The account itself does not appear to be locked because I can sign in normally.

Could someone please advise:

1. Whether error AS(4810) indicates an account-level outbound sending restriction;
2. How the account owner can request Microsoft to review and remove such a restriction; and
3. Whether there are recommended sending practices or limits we should follow in the future when communicating with a legitimate mailing list of student parents to prevent this from happening again?

If Microsoft Q&A cannot access or remove account-level restrictions, please advise how to reach the appropriate Outlook.com/Microsoft support team that can review the account.

Thank you.

Answer 1

Hi SM,

I understand how disruptive this is, especially since even a simple one-recipient message sent directly from Outlook.com is being rejected with 550 5.7.520 AS(4810).

Please note that this is a user-to-user forum, so contributors cannot access your mailbox, review its sending reputation, or remove an account-side sending restriction.

The message indicates that Outlook.com’s filtering system is rejecting the outgoing email as spam. However, the code alone does not confirm the exact reason or whether a mailbox-level restriction has been applied. Since you have already ruled out links, attachments, and multiple recipients, the best next step is to ask Outlook.com Support to review the account privately.

To contact Outlook.com Support:

1. Go to Outlook.com and sign in to the affected account.
2. Select the Help question-mark icon in the upper-right corner.
3. In the Help pane, enter email management, then press Enter.
4. Scroll to Still need help? and select Yes.
5. Select Chat with a support agent in your web browser.
6. Describe the issue and include the complete 550 5.7.520 AS(4810) message. Confirm an alternative email address that you can access.
7. Select Confirm to create the service request. The page should then connect you to Outlook.com live chat support.

Until the account is reviewed, avoid repeatedly resending rejected messages or sending to the full mailing list. For future announcements, reduce the sending volume, divide recipients into smaller groups, and avoid repeatedly sending identical content. Outlook.com limits sending to protect the service from bulk or automated activity, and the applicable limits can vary based on account history.

I hope Outlook.com Support can identify the reason for the restriction and advise on the appropriate next step.