Arduino Portenta x8 RPC

Hi, I'm doing data transfer between Linux and M4 core.
I succeed to transfer the data from controller to the processor.
So I want to send the data from Linux which is processor to the M4 core which is controller.
However when I use server.start() in the Linux, there are no calls any more.
Can I know the way to transfer the data from Linux OS to the M4 core in portenta x8?

Here is my Arduino code and the code for Linux.

I don't know the way how to I solve this problem.. Somebody please help me.