Hi Muzaheed,
Check again your package name, should be like you will use it on google developer console.
If for example your application is fbtest, then it should be com.nameofyourcompany.fbtest, exactly as you configured google developer console and gcm settings on onesignal, not com.YourCompany.fbtest.
For my company that would be com.PandoraEntertainmentLtd.fbtest