User Continually Receives Prompt to Log Into Microsoft Exchange Server

Issue: User is continually receiving a prompt to log into a Microsoft Exchange Server (pop-up window);
Cause: Outlook settings was configured for RPC over HTTPS(outlook anywhere). Outlook anywhere authenticates via Reverse proxy server(ISA server) and would not allow connectivity without valid login credentials. Users on domain do not need to be configured to use outlook anywhere 
follow the steps below to resolve issue:
1. In Outlook have user go to Tools -> Account Settings
2. When Account Settings Window opens click the Change Button
3. In lower right corner user should select More Settings
4. When the More Setting Window appears have them choose the Connection Tab
5. Uncheck the "Connect to Microsoft Exchange using HTTP" box located at the bottom.