The emails I send from MS 365 Personal Outlook are winding up in the recipients spam/junk

Question

About a month? ago, I discovered that when sending emails out, they are landing in the intended recipient's junk or spam folders. Is there a place I can check or something I can do to see if my email got blacklisted?

Answer 1

Hi Nancy Brown,

I understand that messages sent from your Outlook account have recently started reaching recipients’ Junk or Spam folders, and you would like to know whether the sending address has been blocklisted.

Please note that this is a user-to-user forum, so contributors cannot access your account, review its sending reputation, or change how recipients’ mail services classify messages.

The Q&A Assist answer correctly explains that a message delivered to Junk is different from one rejected because of a sending block. Have you had a chance to try the checks provided in that answer?

I would like to add one point to help narrow this down: does this happen with recipients across different email providers, such as Outlook.com, Gmail, and Yahoo, or only with recipients from one provider or organization?

If it happens only with one provider or organization, the classification is likely being applied by that recipient’s mail system. If unrelated recipients across different providers are affected, contact Outlook.com support for an account-specific review:

1. Go to Outlook.com and sign in.  
2. Select the Help icon, the question mark, in the upper-right corner. 
3. In the Help pane that opens, search for "cannot receive emails", then press Enter.   
4. Scroll down the page until you see "Still need help?", click Yes.   
5. Choose "Chat with a support agent in your web browser."  
6. Review the issue description and confirm an email address you can access. 
7. Click Confirm to create the service request. The screen will indicate that your request has been submitted and the system is connecting you to Outlook.com live chat support, which may take a moment to load.  

I hope this helps determine whether the messages are being classified by a particular recipient’s filtering system or whether the Outlook.com account needs further review.

Answer 2

Yes. For mail sent to Microsoft 365 recipients, a blocked sending IP usually shows up as a non-delivery report. A typical example is:

550 5.7.606-649 Access denied, banned sending IP [x.x.x.x]; To request removal from this list please visit https://sender.office.com/ and follow the directions.

If messages are being delivered but landing in Junk instead of Inbox, that is usually treated as a false positive rather than a hard block. Common causes include:

1. Email authentication failure: SPF, DKIM, or DMARC checks failed.
2. Sender reputation: the sending IP address or domain has a poor reputation.
3. Message content triggers: links, URL shorteners, embedded scripts, image-only content, or similar spam-like patterns.
4. Bulk complaint level: the message is being classified as bulk mail.

For a Microsoft 365 Personal Outlook sender, the practical checks are:

1. Send a short plain-text test message to an affected recipient with no links, attachments, images, or signature.
2. Ask the recipient to mark the message as Not spam/Not junk and add the sending address to their contacts or Safe Senders list.
3. Review account activity and settings for anything unexpected, including recent sign-ins, forwarding settings, and connected apps. If anything looks suspicious, change the password and enable multifactor authentication.
4. If a bounce/NDR is received, follow the instructions in that NDR. If it specifically says the sending IP is blocked, use the delist portal named in the NDR.

For incoming mail that is incorrectly going to Junk in Outlook, add trusted senders under Settings > Mail > Junk email > Safe senders and domains.

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