User Configuration > Administrative Templates > Microsoft Office 2016 > Server Settings
User
HKCU\software\policies\microsoft\office\16.0\common\fileio
This policy setting controls file synchronization via SOAP over HTTP. If you enable this policy setting, file synchronization via SOAP over HTTP is allowed only on domain networks. If you disable or do not configure this policy setting, file synchronization via SOAP over HTTP functions on all networks.