This applies to WorkgroupShare v2.3 clients.
The Calendar is selected to be shared and the folder appears in the Administrator, but no items are synchronized to the server. The item count for the shared folder is zero. All other clients see the folder with no contents.
This is caused by a known issue related to the date filtering of the appointments to be shared.
Disable the global date filter for shared appointments. To do this, open the WorkgroupShare Administrator and double click on Settings. Select the Synchronize tab and set the time filter for appointments to Synchronize all appointments.