403 forbidden error message displayed when Calendar Plus tries to aggregate calendar


A 403 forbidden error message is displayed when Calendar Plus tries aggregate a calendar from Microsoft Exchange Server 2007.

Product & Version

Calendar Plus Standard and Professional edition
Version: 4.X.X and below


Calendar Plus cannot connect to exchange 2007 if the “Require SSL” checkbox is checked in Exchange virtual directory. The checkbox is checked by default even if the website doesn’t have SSL.


To resolve the problem you have to check that “Require SSL” checkbox is unchecked:

1. Open IIS Manager on Exchange server
2. Open the properties for the Exchange virtual directory under the default website -> directory security -> Edit for Secure Communications
3. Uncheck “Require SSL”.  

More Information