By default the Server Timeouts setting in Outlook is too low (~1 minute). When the Server Timeouts value is too low, Outlook can behave erratically (sending duplicate messages, not receiving new mail, etc). To increase the value of the Outlook Server Timeouts, follow these directions:

  • In Outlook, open the settings for the account (by clicking Tools then Email Accounts)
  • Once you've opened the settings for your email account, click the More Settings button
  • In the More Settings pop-up window click the Advanced tab. Increase the Server Timeouts value to 5+ minutes
  • Click the "OK" button then click "Next" to close the account settings window

At this point, it is recommend to restart your computer to force-through this adjustment to your Outlook settings.