Development of AR app for Windows Phone 10 - failed initialization

Greetings,
I'm trying to develop a very simple app for Windows Phone 10. Basically, it should show a 3d model over a square target. To do so, I'd like to use the Vuforia kit, which should be easy to use and widely applied. I do everything I see on the related tutorial: I import the asset, set the ARCamera up, set the target and load the 3d model. Then, I build the Visual Studio project and load it into Visual Studio 2015 with the lastest Windows 10 SDK, connect my device and start debugging. Upon loading the app, though, after showing the "Made with Unity" splash page, I only see a black screen and a series of errors, i.e. badimageformatexception. The last error lines say that I have to disable the delayed initialization, but I never toggled it on. What should I do?
I'm using Unity3d 5.5. personal edition with Vuforia 6.2.6 Unity package on a Windows 10 PC.

-MikeT