My personal Hotmail account suddenly stopped sending all outgoing emails after I sent one email containing a WeTransfer

Vicky 0 Reputation points
2026-10-11T21:14:02.9566667+00:00

Hello,

My personal Hotmail account suddenly stopped sending all outgoing emails after I sent one email containing a WeTransfer link to more than 30 recipients.

Since then, even a new plain-text email containing only “Hello” is rejected with error 554 5.7.520, AS(4810). I can still receive emails, and the problem occurs on multiple devices.

Could you please investigate whether my account has been blocked by the Outlook.com outbound spam filter and advise how to restore sending access?

Thank you.

Outlook | Web | Outlook.com | Email
0 comments

2 answers

Sort by: Newest
Most helpful Newest Oldest
  1. Kai-H 28,605 Reputation points Microsoft External Staff Moderator
    2026-10-14T11:26:14.44+00:00

    Hi, Vicky

    The AS(4810) error across every device and recipient strongly suggests a server-side sending restriction, likely triggered by the sudden message volume. Repeated test messages may prolong the restriction, so I would stop sending temporarily.

    Solution: Here are some suggestions you can try:

    Sign out of all Microsoft sessions from Microsoft account > Security > Advanced security options > Sign me out, then wait at least 24 hours before testing again. Do not repeatedly retry during that period.

    Submit a mail-flow review directly at Outlook Consumer Support while signed in with the affected Hotmail account. Include the complete rejection notice, AS(4810), the date and time of the failed message, and its Message-ID.

    Watch for the automated reply and reply to it with the requested details. If you do not respond, the request may close automatically instead of reaching the consumer mail-flow team.

    Please be advised that this is a user-to-user support forum. Moderators and contributors, including external Microsoft employees, are not allowed to directly interfere with Microsoft product features or access back-end systems. Our role is limited solely to providing technical guidance on reported incidents, requests, or ideas.   

    Was this answer helpful?

    0 comments

  2. AI answer

    2026-10-11T21:14:19.3033333+00:00

    The behavior matches a sending restriction or spam filtering event on the Outlook.com side after a message with a link was sent to many recipients.

    Use this recovery path:

    1. Send a simple test message in Outlook.com
      • Sign in to Outlook.com in the browser.
      • Send a new plain-text message with no links, no attachments, and only one recipient.
      • This confirms whether the restriction affects all clients, which fits the multi-device symptom described.
    2. Check whether the account is newly created or still building reputation
      • Outlook.com applies a temporary low sending quota to new accounts until credibility is established.
      • If the account is newer, this can temporarily limit sending.
    3. Review the non-delivery report details
      • Outlook.com states that delivery failures usually include the reason.
      • For errors that mention messages being blocked or listed in spam/block lists, the message was intentionally blocked by a spam or blocklist filter.
    4. Reduce spam-like signals before retrying
      • Do not resend to large recipient batches.
      • Remove links and attachments.
      • If sending to a group, reduce the number of recipients.
      • If a signature is configured, remove it and resend, because signatures can affect sending.
    5. Check basic Outlook.com sending conditions
      • Make sure the message is not stuck in Drafts or Outbox.
      • If the mailbox is full, clear space because a full inbox can prevent sending and receiving new mail.
      • If any attachment is over 25 MB, remove it or upload it to OneDrive and attach a link instead.
    6. If the account was flagged after suspicious activity, secure it
      • Review recent sign-in activity.
      • Change the password if anything looks unfamiliar.
      • Check Sent items, rules, and forwarding for anything unusual.
    7. If sending is still blocked, contact Outlook.com support from within Outlook.com
      • In Outlook.com, select Help on the menu bar, enter the issue, and if self-help does not solve it, scroll to Still need help? and select Yes.
      • If sign-in is also affected, use the Outlook.com support entry point provided on the support page.

    What can be concluded from the reported symptoms:

    • Because receiving still works and sending fails on multiple devices, the issue is unlikely to be device-specific.
    • Because even a plain-text “Hello” message now fails, the original message likely triggered a sending restriction or spam classification rather than a problem with only that one message.
    • Account-specific block status cannot be directly investigated here, but Outlook.com support is the path for review when the restriction persists.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.