Sometimes you'll get a timeout error on Outlook when using the synchronized IMAP or if your connection is interupted or slow.
- Click "File" from the top ribbon.
- Click Account Settings and then Account Settings from the dropdown.
- Select the account you want to modify and then click the Change button
- Click the More Settings button.
- Click the Advanced tab.
- Under "Server Timeouts" slide it to the far-right (10 minutes).
- Click "OK" >> "Next" >> "Finish" to save these new settings.
That should fix the issue, or at least minimize the connection timeout error from coming up.