Outlook emails not received

Check the mailbox in Outlook on the web immediately after a controlled test message; this determines whether the message is failing before mailbox delivery or is present in the mailbox but missing only from the Windows desktop client.

1. Run a controlled delivery test

Ask one affected sender to send a new message with:

• A unique subject, such as Delivery test 2026-11-09 14:30
• No attachment or embedded image
• Only your Outlook address in To
• Your Gmail address in CC

Record the exact sending time and ask the sender to retain any non-delivery report (NDR/bounce).

Then check the same Microsoft mailbox in its web interface—not merely another view in desktop Outlook:

• For a personal @outlook.com, @hotmail.com, @live.com, or @msn.com account, use Outlook.com.
• For a work or school Microsoft 365 account, use Outlook on the web provided by the organization.

Search the unique subject across Inbox, Other, Junk Email, Deleted Items, and Archive. Also check mailbox rules and forwarding. Microsoft lists filtering, forwarding, rules, Junk, and sorting among the mailbox-level causes of missing Outlook.com messages.^1^

Because Safe Senders has already been configured, do not keep modifying that list. It affects junk handling after a message reaches the relevant filtering stage; it cannot recover a message rejected before mailbox delivery.

2. Act on the result

Message appears on the web but not in desktop Outlook

The mailbox received it, so the remaining issue is desktop display or synchronization.

1. Search All Mailboxes in desktop Outlook using the unique subject.
2. Clear the current view’s filters and sort by Date.
3. Check whether the message appears in another folder or only under the Other tab.
4. Compare the desktop rules with the rules visible on the web.

Microsoft specifically recommends checking the Other tab, sorting, forwarding, and rules when expected messages are not visible.^1^

If the message exists on the web but remains absent from desktop Outlook after those checks, contact Microsoft 365 support and report it as a desktop synchronization/display issue, including the Outlook version, account type, unique subject, and sending time.

Message does not appear on the web

This is not primarily a Windows 11 or Outlook desktop problem. Continue with the appropriate mailbox path below.

Work or school Microsoft 365 account

Ask an Exchange or Microsoft 365 administrator to run a message trace:

1. Open Exchange admin center → Mail flow → Message trace.
2. Select Start a trace.
3. Enter the affected external sender and your recipient address.
4. Set a narrow time range around the test.
5. Run the trace and open the message details.

Message trace identifies whether Microsoft 365 received, rejected, deferred, quarantined, filtered, redirected, or delivered the message. It requires Exchange administrative permissions.^2^

Interpret the result as follows:

• Quarantined: Have the administrator review and release it where policy permits. Some detections, including malware and high-confidence phishing, cannot be released directly by recipients.^3^
• Filtered as spam / Failed: Open the event details to identify the filtering policy, rejection, connector, or mail-flow rule.
• Delivered: Check the destination folder and any rule, redirection, or deletion event. Message trace can show whether a rule redirected or quarantined the message.^4^
• No result: Microsoft 365 might never have received the message; obtain the sender’s SMTP logs or NDR.

Personal Outlook.com/Hotmail account

Ask each affected sender for the complete NDR, including the numeric status code. If no NDR exists, have the sender follow Microsoft’s Outlook.com sender-deliverability guidance.^5^

Apply these code-specific remedies:

• 5.7.511 Access denied or “banned sending IP”: The sender—not the recipient—must visit https://sender.office.com, enter the address that received the NDR and the sending IP shown in it, complete verification, and select Delist IP.^6^
• 550 5.7.515 with SPF/authentication failure: The sender’s mail administrator must correct the domain’s email-authentication configuration. A Safe Senders entry cannot override a rejection that occurs before delivery.^7^
• No NDR and no message anywhere: Contact Outlook.com support from Help → Still need help?, supplying the sender, recipient, exact UTC time, subject, and any sender-side message ID or SMTP logs.^1^

References

1. Can't send or receive email in Outlook.com | Microsoft Support
2. Message trace in the Exchange admin center in Exchange Online
3. Quarantined email messages in cloud organizations
4. Message Trace FAQ in Exchange Online
5. Sender Support in Outlook.com
6. Can't receive emails from certain senders - Microsoft Q&A
7. Why am I not receiving emails from certain senders that I haven't blocked? - Microsoft Q&A