1. Verify Microsoft Service Status
- Visit official status pages:
- status.live.com
- portal.office.com/servicestatus
- If there’s a known outage or scheduled maintenance, it’s best to wait until it’s resolved.
2. Remove and Re-Add Your Microsoft Account
- Go to Outlook → File → Account Settings → Manage Profiles.
- Remove the affected account.
- Restart Outlook and re-add the account from scratch to reset the sync environment.
3. Install the Latest Updates
- Ensure both Windows and Outlook are fully updated:
- For Outlook: File → Office Account → Update Options → Update Now
- For Windows: Settings → Windows Update → Check for Updates
- These updates often include patches for mail sync components and authentication modules.
4. Clear Stored Credentials
- Open Control Panel → Credential Manager → Windows Credentials.
- Delete any saved entries for Outlook, MicrosoftAccount, Office, or live.com.
- This will force Outlook to request fresh credentials the next time you log in.
5. Reset Mail App or Outlook Profile (Optional)
- For Windows Mail app users:
- Go to Settings → Apps → Mail and Calendar → Advanced Options → Reset
- For Outlook users:
- Navigate to Control Panel → Mail → Show Profiles
- Create a new profile and set it as default to eliminate corrupted local configurations.
6. Use Network Diagnostics
- Run Windows Network Troubleshooter:
- Settings → System → Troubleshoot → Other troubleshooters → Internet Connections
- Check proxy settings, disable VPNs temporarily, and test using a different network to rule out firewall or ISP restrictions.