code not executed when using Backendless.UserService.loginWithFacebookSdk


need some help. i have setup my codes as per the documentation for android .
using the Backendless.UserService.loginWithFacebookSdk to login , when executed , the callback callbackManager.onActivityResult(requestCode, responseCode, data) was executed but the none of the functions in AsyncCallback was called.

please advice on this

sorry , you can close this. manage to solve it . looks like something wrong with my debugger