One customer reported the following issue: People Search is not working. After clicking Connect the list of fields is empty and connected ShortPoint doesn't show any item.
The People Search Connection type relies completely on SharePoint People Search. So the first thing you should check if SharePoint Search is configured and working on your environment. Most probably it's not and the issue can be resolved by configuring it.
If it didn't solve the issue - please, submit a support ticket, and we will check it.