Hi we are using Portal for ArcGIS and Web Adaptor 10.4 which are configured with IWA and Windows Authentication. We have setup a webmap which contains a number of layers from ArcGIS Server map services. Both Portal and ArcGIS Server are configured with HTTPS only. The webmap is shared to a a particular portal group, which the user is a member of.
We have then built a web application using WAB Developer Edition, and hosted on a separate web server.
When using the Out of the Box Print or Measurement widget from the web app, it prompts for login to the portal (attached)
Has anyone come across a similar issue?
Did you ever get this figured out? Since you are using https it is requesting a user that has permissions to that location. We have the same setup on our network using a proxy server. In WAB when accessing secured services via https it prompts us for a user name and password to access our "secured" rest services. We were able to add the path (in your screenshot) of the location with the user and password in a proxy file. From there we host the proxy file in iis and reference it in the root directory of the application created "config.json". Message me if you need any further help. Surely someone has helped you since 5/2016.