web deployment error

[mandrosen]

OS X 10.11.5
Version: Neon Release (4.6.0)
Build id: 20160613-1800

I can setup an SFTP connection with the Web Deployment Wizard for a project. If I open a file and click on the 'Publish' context menu item, the download/upload buttons are greyed out. If I expand the connection at the bottom of the project (in Project Explorer) and click on 'File Transfer->Download', I get this error:
An internal error occurred during: "Downloading...".
org.eclipse.core.internal.filesystem.Policy.subMonitorFor(Lorg/eclipse/core/runtime/IProgressMonitor;I)Lorg/eclipse/core/runtime/IProgressMonitor;