1. Check Your Internet Connection
- Restart your modem/router.
- Switch to a different network if possible.
- Avoid public or restricted networks that may block email traffic.
2. Temporarily Disable Firewall or Antivirus
- Disable third-party firewalls or antivirus programs briefly to test if they’re blocking Outlook’s connection.
- If this resolves the issue, configure an exception for Outlook in your security software.
3. Clear Proxy and DNS Settings
- Open Command Prompt as Administrator.
Run:
netsh winhttp reset proxy
ipconfig /flushdns
- This clears incorrect proxy configurations and refreshes DNS settings.
4. Repair Outlook Data Files
- Use ScanPST.exe (Inbox Repair Tool) to check and fix PST/OST corruption.
- Navigate to:
- C:\Program Files\Microsoft Office\root\OfficeXX\SCANPST.EXE
5. Update Windows and Outlook
- Go to Settings → Update & Security → Windows Update and install any pending updates.
- Update Outlook from File → Office Account → Update Options → Update Now.
6. Verify Server Configuration
- Make sure Outlook is pointing to the correct server address, port numbers, and encryption type.
- Use your provider’s official support page to confirm your configuration matches current standards.
7. Try Outlook in Safe Mode
- Press Windows + R, type Outlook /safe, and press Enter.
- If it works in Safe Mode, the issue may be caused by an add-in or third-party extension.