Not receiving emails from sender who had previously sent emails. (Outlook)

Question

Not receiving emails from sender who had previously sent emails. (Outlook)

Christine McNeely 0

I am not receiving emails (Outlook) from a specific email sender. Have previously received emails from them. Their email address is not blocked and is on safe senders list. They are receiving an error message on their end. Is there a way to fix this.

2 answers

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Answer 1

Christine McNeely 0

[Moderator Note: Personal Info Removed]

Answer 2

Chloe-L 10,340 Microsoft External Staff Moderator

Hello Christine McNeely,

Thank you for posting your question to the Microsoft Q&A forum. I understand how frustrating it is to suddenly stop receiving emails from a trusted sender, especially when you have already verified they are on your Safe Senders list and not blocked.

Based on the details you provided—specifically that the sender is receiving an error message on their end—this is actually the most critical piece of information. This indicates that the issue is likely a server-side rejection rather than a local setting on your Outlook client (like a Rule or Filter).

To resolve this, we need to analyze that specific error to understand why the server is blocking the hand-off. Could you please ask the sender to copy and paste the full "bounce back" message or Non-Delivery Report (NDR) they are receiving?

Please look for specific details in that message, such as:

Error Code: (e.g., 550 5.1.1, 550 5.7.1, etc.)
Reason for rejection: (e.g., "Message blocked," "Mailbox full," "Spam detected," or "Access denied")

Once you share that error code here, I can pinpoint exactly what is causing the blockage and provide the correct solution to fix it.

I hope this helps us get to the bottom of the issue. Please reply with the error details when you have them.

Christine McNeely 0 Reputation points

2026-02-25T22:26:30.18+00:00

[Moderator Note: Personal Info Removed]
Chloe-L 10,340 Reputation points Microsoft External Staff Moderator

2026-02-25T22:58:36.42+00:00
Dear Christine McNeely,

Thank you for the update and for sharing that specific error message. This is excellent news because it confirms exactly where the problem lies.

Note: To protect your privacy, I have removed the image you uploaded as it contained personal information.

Based on the error "rate limited due to IP reputation," this confirms that your account is working perfectly fine. The issue is entirely on the sender's side.

Microsoft's security filters monitor the "reputation" of all email servers trying to send mail to Outlook/Hotmail. Currently, the server used by the sender has a low reputation score (likely due to sending bulk emails or previous spam reports), so Microsoft is temporarily blocking their emails to protect your inbox.

Unfortunately, to resolve this, action is required from the sender's side. Since this block is enforced by Microsoft's global servers to protect against potential spam, there are no settings within your personal Outlook account that can bypass this specific restriction.

Please copy and paste the message below and send it to the sender (via text, another email address, or phone) so their IT team knows exactly how to unblock themselves:

"Hello, I am unable to receive your emails at my Outlook/Hotmail address. The error message indicates: '421 4.7.0 ... temp rate limited due to ip reputation'.

This means your sending IP address has been throttled by Microsoft's Smart Network Data Services (SNDS). To restore delivery, your email administrator needs to:

Check the status of your IP address at the Microsoft SNDS Portal.

Submit a delisting request specifically for Outlook.com delivery issues using the Sender Information for Outlook.com Delivery form.

Once Microsoft Support reviews your IP and mitigates the reputation score, the emails will start arriving again."

I hope this explanation clarifies why the emails aren't arriving and helps you get the solution to the right person.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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Not receiving emails from sender who had previously sent emails. (Outlook)

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