Message: "folder missing" in sync window

My Cloud OS 3 Personal & Network Attached Storage My Cloud Mirror
1

When I look in the system tray at the WD icon there is a message saying “LawFirm is missing”. with an arrow to drop down (nothing in the drop down. Lawfirm is the name of the folder I sync with mycloud. Usually there is a list of documents that are syncing.

Has anyone seen this before or know what I can do

Thanks

Peter