Crash on Prime31 Twitter login when built with il2cpp

I am using the Prime31 twitter unity plugin to support twitter in my games. Currently I am facing crash on twitter login while the game is built with il2cpp (Built with Unity 4.6.3) and run on 64bit device with iOS 8.x. Same build works fine on 32bit devices. The same issue exists when built with Unity latest patch 4.6.3p3 also. Has any one come across this issue. Any one has any solution for this issue ?