I followed the instructions and tryed problem solving with Rebeccas tips but still no success with running the Web Application Builder v.1.2.
Machine is a personal computer, Win 7, browser Firefox or Chrome. My account is a free ArcGIS Dev. account.
Usually I work with the Story Map application and use XAMPP to test my stuff, The instruction is clear to register with the (full) computer name, say: "uxxxxxx". No Domain but Workgroup "WORKGROUP". Redirection URIs would be:
In AGOL: My Content/ Add Item / An Application / URL:
http://uxxxxxx:3344/webappbuilder/
Redirect URI:
http://uxxxxxx and https:uxxxxxx
Portal URI:
http://x3lt.maps.arcgis.com/