CAN bus communication between RPi and Arduino
Change
while (CAN_OK != CAN.begin(CAN_125KBPS))
to
while (CAN_OK != CAN.begin(CAN_500KBPS,MCP_8MHz))
And
bus = can.interface.Bus(can_interface,bustype='socketcan’,bitrate=500000)
And
In /boot/config.txt (in RPi)
Set oscillator=8000000
Finally ensure bitrate and clock are same in both RPi and Arduino