“Communication was blocked, perhaps by your computer’s firewall settings, to a web service that is required by Microsoft Dynamics CRM.”
Unblock URLs required for Microsoft Dynamics CRM Online
Microsoft Dynamics CRM for Outlook client crashes when using a Proxy PAC file
(407) Proxy Authentication Required Exception
If you are still encountering issues connecting CRM for Outlook to your CRM Online organization, run the Microsoft Support and Recovery Assistant to diagnose and fix the problem.
Article ID: 2997744 - Last Review: 6 Jun 2016 - Revision: 1