Error Code 0x8015DC12 is seen when errors in the sign-in process for xbox.com with the Xbox One with universal Windows applications. This is not generally seen outside developer accounts etc.
Some things to watch out for are:
- Ensure your App ID is entered into XDP or Partner Center correctly
- Ensure your PFN is entered into XDP or Partner Center correctly
- Double-check you have created an xboxservices.config in the same directory as your Visual Studio project as described in the Adding Xbox Live to a new or existing UWP project guide.
- Ensure that the “Package Identity” in your appxmanifest is correct. This is shown in Partner Center as “Package/Identity/Name” in the App Identity section.
In the solution explorer try removing the PFX files.
If you didn’t sign-in to Visual Studio with the Microsoft Account used for provisioning the app in Partner Center, Visual Studio will auto generate a signing pfx file based on your personal Microsoft Account or your domain account. When building the appx package, Visual Studio will use that auto generated pfx to sign the package and alter the “publisher” part of the package identity in the package.appxmanifest. As a result, the produced bits (specifically, the appxmanifest.xml) will have a different package identity than what you intend to use.