Why events cannot be displayed when using the “Use current logged-in user’s windows credentials” in Calendar Plus Web Part?
Product & Version
KWizCom Calendar Plus Standard Evaluation 4.x.xx for SharePoint 2007
KWizCom Calendar Plus Standard Evaluation 14.x.xx for SharePoint 2010
You cannot use the “Use current logged-in user’s windows credentionals” if your Exchange server and SharePoint servers are two different servers. By default you cannot delegate permission from one server to another. You will need to make some modifications on your domain to do that.
The following article refers to the process of how to make domain controller trusted for delegation: