We're running Outlook 2013 with exchange. Users have Sharepoint 2007 calendars linked to their Outlook accounts. Recently, Outlook has started prompting users for their sharepoint credentials when Outlook performs a send/receive for the first time after being opened. Even after the 'remember credentials' box is selected, Outlook continues to prompt for credentials upon the first send/receive. Here are the steps I've tried so far to resolve this issue: 

Removed and re-added Sharepoint Calendar. 

Removed Outlook Profile and re-added

Removed sharepoint credentials from credentials manager and re-added credential under general credentials.(The credentials box was initially empty upon each prompt, but after this step the username and password was automatically filled. However, the credentials box still appeared)

Tried adding a password to the Calendar file itself under Account Settings > Data Files > Sharepoint list > Change Password. 

Added Sharepoint to list of trusted sites in IE and changed user authentication levels in custom levels to automatic login with current username and password. Also tried to add to intranet list.

Cleared IE settings and passwords. 

I've seen several people with similar issues but nothing quite the same, or the issue was resolved through the steps above. 

Thanks in advance for any help.

• Edited by jamestoto 1 hour 2 minutes ago