Android API 23 has trouble with our engine, which is why we suggest you use latest, matchndk or (21). I did verify that using 23 does cause an error with our engine.
SDK API Level set to “latest” will use
the highest number found installed. If
you have API-23 installed, you should
change the SDK API Level from “latest”
to “matchndk” or “android-21” (check
your SDK’s platforms directory for
which versions are available). It is
OK for SDK to be set higher than NDK.
[Android SDK & API 23 Forum Post][1]
Android SDK and API 23 - Mobile - Epic Developer Community Forums