Sign in to Outlook on the web first; whether new messages appear there determines if this is a mailbox delivery problem or two separate app-sync problems.
1. Test the mailbox itself
- Open Outlook on the web using a browser on the Surface.
- Send a test message to the affected address from another email account.
- Check Inbox, Other, and Junk Email.
- Select Filter → Sort → Date to ensure recent messages appear first.
Then follow the matching result:
- The test message appears online: the mailbox is receiving mail; continue with the device-sync steps below.
- It does not appear online: skip to “If mail is also missing online.”
2. If mail appears online, repair both apps
Surface
First identify the Windows Outlook version:
- Classic Outlook: the New Outlook toggle is off. Run Microsoft’s Classic Outlook send/receive troubleshooter. Microsoft notes that these troubleshooters do not apply to new Outlook for Windows.^1^
- New Outlook: remove the affected account from Outlook and add it again, completing the normal Microsoft sign-in process.
If the address belongs to Yahoo or another provider rather than Microsoft, use that provider’s current authentication and server settings. Some providers require an app password. When the mailbox is used on multiple devices, configure it with IMAP rather than POP so messages synchronize between them.^2^
iPhone Outlook app
- Open Outlook → profile picture → Settings.
- Select the affected account.
- Tap Delete Account → Delete From This Device.
- Add the account again and complete its sign-in prompts.
Microsoft recommends removing and re-adding an Outlook.com or Microsoft 365 account when it has stopped syncing.^3^
If Outlook itself freezes or crashes instead:
- Close Outlook from the iPhone app switcher.
- Restart the iPhone.
- Update Outlook from the App Store.
- If necessary, open Settings → General → iPhone Storage → Outlook → Offload App, then reopen it.^3^
3. If mail is also missing online
This is a mailbox-level issue, so reinstalling either app will not restore delivery.
For an Outlook.com, Hotmail, or Live account:
- Check Microsoft cloud and mailbox storage. When Microsoft cloud storage is full, Outlook.com cannot send or receive mail; messages sent while it was full are bounced and cannot later be recovered.^4^
- In Outlook on the web, inspect:
- Other
- Junk Email
- Settings → Mail → Rules
- Settings → Mail → Forwarding
- Blocked senders
- If the password was changed recently, update it and complete any account-unblock prompt.
- Check Microsoft’s public service-health page for an Outlook incident.^5^
For a Microsoft 365 work or school account, an administrator should also check Microsoft 365 admin center → Health → Service health for tenant-specific Exchange Online incidents.^6^
If delivery still fails, provide the email provider or administrator with:
- The exact email address domain, such as
@outlook.com or a company domain
- Time the last message arrived
- Whether sending still works
- Any error or non-delivery message received by the sender
References
- Issues sending and receiving email | Microsoft Support
- outlook on pc won't connect. works fine on iphone - Microsoft Q&A
- Troubleshoot Outlook mobile issues | Microsoft Support
- Can't send or receive email in Outlook.com
- Microsoft service health status
- How to check Microsoft 365 service health