Impossible to say without more information.
-Are you using any non official plugins?
-Does the compile log in XDK look ok?
-Do you use minify on export from construct2?
-Does other games work for you on export on your device(try a simple demo project and see if that works out of the box on your device)
-Do you see any error in Chrome in its Console? (press F12)
There are a thousand things that can go wrong....start simple and test often!