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EMAIL TROUBLESHOOTING
Missing email is sometimes a glitch, and sometimes a warning sign.
Outlook email not syncing? Causes and fixes for business
Mail shows on your phone but not in Outlook, sent items are missing, or messages stop arriving. Most sync problems have simple causes. A few mean someone else is in your mailbox. Here is how to tell which.
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The short answer
- Check webmail first at outlook.office.com. If mail is there, the problem is your Outlook app or phone, not the mailbox.
- Full mailboxes stop receiving mail. Check the storage bar and archive old mail.
- A changed password or MFA prompt that was never completed stops phones and Outlook from syncing.
- A damaged Outlook profile or cache can be rebuilt without losing mail on Microsoft 365.
- If messages vanish or replies never arrive, check for strange inbox rules. That can mean a hacked account.
Common causes and fixes
| What you see | Likely cause | Fix |
|---|---|---|
| Mail in webmail but not in Outlook | Outlook offline, cache or profile issue | Turn off Work Offline, restart, rebuild the profile |
| Phone stopped getting mail | Password changed or sign in needed | Sign in again in the Outlook app |
| Nobody can send to you | Mailbox full | Archive or clean up, or add archive storage |
| Some messages missing | Junk folder, Focused inbox or a rule | Check Junk, Other and inbox rules |
| Replies from one vendor never arrive | Rule hiding them, possible break in | Delete unknown rules, reset password, check sign ins |
| Shared mailbox or calendar not updating | Permissions or cache | Reapply access and refresh |
When it is a security problem
🔃Unknown rulesRules moving mail to RSS or Archive folders, or forwarding outside.
📤Sent mail you did not sendEspecially invoices or payment changes.
🌎Strange sign insLogins from other states or countries.
🔒Act fastReset the password, sign out all sessions and call us. See Microsoft 365 security.
How WENO fixes email problems
1. Remote checkWe look at the mailbox, rules and sign ins from the admin side.
2. Fix the deviceOutlook profile, cache and phone setup repaired without losing mail.
3. Clean up storageArchiving and retention set so mailboxes do not fill again.
4. Secure itMFA, alerts for risky rules and blocked outside forwarding.
Questions people ask
Will rebuilding Outlook delete my email?
Not on Microsoft 365. The mail is stored on Microsoft's servers and downloads again. Older local data files are checked first.
Why does my phone keep asking for my password?
Usually a password change, an MFA step or an old mail app. The Outlook app with modern sign in fixes most cases.
Get your email flowing again.Remote help, and a security check while we are in there.
Fix my emailGeneral information. Steps vary by Outlook version and device.