Outlook returns HTTP 404 when syncing Contacts or Calendars (WSS) When using Outlook 2007 to sync contacts or calendars, Outlook returns 'HTTP 404' error after about 30 seconds with no further information. If the calendar or contacts (WSS) you are linking contains a lot of information Outlook may timeout before all of this has been received.

This can result in a 404 error saying it couldn't connect to a SharePoint list.

Resolution

Outlook has a default timeout of 30 seconds when trying to receive data from the calendar/contacts server. The timeout value should be increased to overcome this problem.

• Add a ReceiveTimeout DWORD value with a data value of (number of seconds)*1000 in the following registry key:
  HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
• For example, if you want the timeout duration to be 8 minutes, set the ReceiveTimeout data value to 480000 (480*1000) (decimal).
• Restart your computer.
• Perform a send/receive. The value may need to be increased if the error continues.