Hotmail account: all outgoing mail to Microsoft 365 recipients rejected with [moderator's note: PII removed]

Question

Hotmail account: all outgoing mail to Microsoft 365 recipients rejected with [moderator's note: PII removed]

TARPADE MIANMARDE Stéphane 0

Hello,

[moderator's note: PII removed], every email I send from my personal Hotmail address to recipients hosted on Microsoft 365 is rejected with:

[moderator's note: PII removed] Message blocked because it contains content identified as spam. [moderator's note: PII removed]

What I observed:

It affects a company domain (Microsoft 365) AND Microsoft's own support mailbox, so it is not specific to one recipient.
The same message sent from a Gmail account is delivered normally.
The content does not matter: new thread, blank message, plain text, no signature, Outlook web, Thunderbird, Windows Mail. Same result.
My account shows no sending restriction and no suspicious sign-in (recent activity checked).
sender.office.com finds no blocked IP, which is expected: this is not an IP block, it seems to be an outbound spam classification of my account.
The Outlook.com Deliverability Support team told me they are not the right place and sent me here.

These are personal, low-volume emails (job applications). I only receive the bounce, which is the only error message I have.

Can a Microsoft moderator or someone from the Outlook.com team review the outbound classification of my account and remove it? I can send full headers privately if needed.

Thank you.

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Answer 1

For your privacy and security, I have covered the personal information included in your post. Please avoid sharing any personal or sensitive information publicly, such as serial numbers, order details, email addresses, phone numbers, or case-related information.

Hi TARPADE MIANMARDE Stéphane,

Thank you for documenting the tests you have already performed. Since the same rejection occurs with different recipients, message content, and mail applications, this does not appear to be limited to one recipient or to a particular email client.

The error indicates that the outgoing message is being rejected by Microsoft’s filtering system as suspected spam. Microsoft’s anti-spam filters can occasionally classify legitimate messages incorrectly, but the detailed filtering criteria for an individual message are not publicly disclosed.

Unfortunately, moderators and contributors in this user-to-user forum cannot access the internal reputation or outbound classification of a personal Outlook.com account, nor can we manually remove such a classification. Since the Outlook.com Deliverability team has already confirmed that its sender-support process is not the appropriate route for this scenario, the next step would be to contact Microsoft Support while signed in with the affected Hotmail account.

When contacting Support, provide the complete non-delivery report, including the spam code, the date and time of a recent failed message, and the generating server details. You can also explain that the issue affects multiple Microsoft 365 recipients and occurs even with blank plain-text messages sent from Outlook on the web. If the Support Assistant appears, enter:

“I need a live support agent to review a possible incorrect outbound spam classification.”

Please share the full headers only through a private Microsoft Support channel, as they may contain email addresses, server information, and other account-related details. Thank you so much for your understanding.

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