I have several web apps in portal which have secured REST endpoints in them. It will prompt the user for their windows username and password. If they are authorized to see the REST endpoints then the map opens with those layers. If they are not then it either keeps prompting them for their username and password, or shows the basemap and has an endless spinning load icon. Is there a way to redirect to url which will tell the user then are not authorized to see the map layers if their username/password will not authorize them to open the REST end points for the Portal Web App.