My, isc.REST code at below. UnkownUser is enabled. I just  download Evaluation edition. Not,  production edition. So, just trial. Is it obstacle for it?

Include isc.REST

/// Class for REST-like web api.<br>
/// Logic related to request processing goes here.
Class isc.REST Extends isc.AbstractREST
{

XData UrlMap
{
<Routes>
   <!-- Test method-->
   <Route Url="/test" Method="GET" Call="Test"/>
   <Route Url="/logout" Method="GET" Call="Logout"/>
 </Routes>
}

/// End session
ClassMethod Logout() As %Status
{
#dim %session As %CSP.Session
set st = %session.Logout(1)
set %session.EndSession = 1
return st
}

/// Test method, outputs <b>%request</b>, <b>%response</b> and <b>%session</b> objects.
ClassMethod Test() As %Status
{
    write "{""Status"": ""OK""}"
    return $$$OK
}

}