JY_MCU Board problem (Connected to Arduino UNO)

Using Arduino Networking, Protocols, and Devices
3

dxw00d:

SofrwareSerial mySerial(0,1); // RX, TX pins

That line won't compile, but assuming it's correct in your real sketch, why are you trying to do software serial on the hardware serial pins?

Is it the source of problem? What should I do instead?
By the way, it is compiling. (of course without the spelling mistake, correctly would be SoftwareSerial)