Utilizing the listed options for adding a new Elastica Securlet for monitoring in the DLP Enforce UI, you find that it is not completing its "sync" successfully.
There are currently a few Securlets which are NOT supported for Application Detection, despite being included in the v15 list of apps.
Currently, the following is not a valid Securlet (as of February 2019):
Also, the following Securlet is in "Beta" in Elastica CloudSOC, so is also not supported for DLP Detection at the moment:
While there are Gatelets for both Facebook Workplace and Microsoft Teams, they are not currently supported for DLP detection.
Remove the unsupported apps, then re-click the "Cloud Sync" option in the UI.
FYI - although the Cloud Detection Server cannot monitor "Microsoft Teams" activity via that Securlet, content shared via the application is picked up via O365 Securlets, where the file is shared via a path in SharePoint.