mbed rosserial Unable to sync with device; possible link problem or link software version mismatch such as hydro rosserial_python with groovy Arduino

Hello guys, I'm new at ROS and I'm using ros-kinetic in mbed platform. In terminal, when I type this command: rosrun rosserial_python serial_node.py /dev/ttyACM0 _baud:=9600 I get these: [INFO] [1561209329.707241]: ROS Serial Python Node [INFO] [1561209329.727014]: Connecting to /dev/ttyACM0 at 9600 baud [ERROR] [1561209346.833194]: Unable to sync with device; possible link problem or link software version mismatch such as hydro rosserial_python with groovy Arduino I googled it but can't find a working solution. What should I do?