Not connect C++ TCP Server..

I'm make C++ TCP Server(based WinSock2).
Unity client make by C# code(System.Net.Sockets.Socket class).
It was success community connect that unity play.
And I build android(Android 2.3.1 "Gingerbread").

Create "APK" file, at install android device.
Let's connect C++ TCP Server...
However, it was failed community connect...
TCP Server no response, remain unchanged TCP State "Listening"
Why not response C++ TCP Server?
Server is staying accept()...

Hope someone can help me with this!. Thanks!