Message blocked because it contains content identified as spam

Eric Rolf 0 Reputation points
2026-10-04T01:59:53.9+00:00

After increasing storage for one drive, my outlook is not alllowing me to send emails as get note: Message blocked because it contains content identified as spam but can receive emails

Outlook | Windows | New Outlook for Windows | For home
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  1. AI answer

    2026-10-04T02:00:10.2533333+00:00

    This usually means the message is being flagged by spam filtering, not that Outlook.com is unable to receive mail. Since mail can still be received, focus on what is in the message being sent.

    Try these steps in order:

    1. Send a plain-text test message with no attachment, no signature, and no links.
      • If that sends successfully, the block is likely caused by message content, formatting, or an attachment.
    2. Remove the email signature and try again.
      • Outlook.com signatures can affect sending in some cases.
    3. Check attachments.
      • Outlook.com can’t send attachments larger than 25 MB.
      • Outlook also blocks certain attachment types such as .exe and some database files.
      • If the file is being flagged, save it to OneDrive and send a sharing link instead.
    4. Simplify the message content.
      • Messages can be flagged as spam because of content, links, images, or attachments.
      • If the message is HTML, switch to plain text as a test.
    5. Verify storage is no longer full.
      • If Microsoft cloud storage or mailbox storage is full, Outlook.com can’t send or receive email.
      • After getting back under quota, previously bounced incoming messages are not recoverable and must be resent by the sender.
    6. Check the account state.
      • If the password was changed recently, update it.
      • If unusual sign-in activity was detected, the account might be temporarily blocked and may need to be unblocked.
    7. If a non-delivery report is returned, review the reason in that report.
      • Common causes include spam filtering, invalid recipient address, recipient mailbox full, or recipient server issues.

    If the problem happens only when sending attachments, the most practical workaround is to send the file through OneDrive as a link instead of attaching it directly.

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

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  2. Hendrix-V 19,655 Reputation points Microsoft External Staff Moderator
    2026-10-04T06:27:35.8166667+00:00

    Hi Eric Rolf,

    Since the error is occurring when sending but not receiving email, it may be worth checking whether the sending capability of the account has been temporarily restricted.

    You can try the following checks:

    • Sign in to your Microsoft account and review Recent activity for any unusual sign-in attempts. If prompted, complete any account verification steps.
    • Test sending from a different network connection (for example, mobile data or another Wi‑Fi network) to rule out a reputation-related block associated with the current connection.
    • If you use an Outlook.com account, try sending from the Outlook web interface and note whether the same error appears there. This can help determine whether the issue is account-related rather than device-specific.

    If the problem affects every message and persists across devices, you may need to contact Microsoft Support for account review, as sending restrictions can sometimes require investigation on the service side.

    Please note that this is a user-to-user support forum. Moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. Our role is limited to providing technical guidance on reported issues, requests, or ideas.

    I hope this helps. Let us know what you find, and the community will be happy to help further.

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