Disable HTTP fallback for SIP connection

Supported on: At least Windows Server 2008 R2 or Windows 7

Registry

HKLM software\policies\microsoft\office\16.0\lync

Value name: disablehttpconnect

Enabled: disablehttpconnect = 1

Disabled: disablehttpconnect = 0

Prevents from HTTP being used for SIP connection in case TLS or TCP fail.