I had Esri Maps for Office 2.x working perfectly with my ArcGIS for Portal 10.3 (with dedicated hosting ArcGIS for Server 10.3). Everything worked as expected. I recently upgraded to Esri Maps for Office 3.0, and suddenly I can't log in. When I click the sign-in button, instead of being presented with my Portal's login page, I get en error that says Invalid redirect_uri Error:400. Any thoughts on what's going on here?