Cannot hook MsgBox

[Ebenezer Scrooge]

This is the window I want to hooked.

This is the result analysed by Spy++

I use the code about AppHook in README.MD, but I cannot see output about the MsgBox I want to hook.

This is the code I wrote following the demo in README.
If you can give me some advice or hints, I will be appreciate it, Thx !!!