Since I do not have this board I had to do a little digging and found that Serial seems to be the UART pins, not for printing over the USB.
To print over the USB serial port replace “Serial” with “SerialUSB”.
This is similar to how the Arduino DUE and ZERO work as well which are also SAMD21 processors. Let me know if this works.
So…
void setup() {
SerialUSB.begin(9600);
while(!SerialUSB);
}
void loop() {
SerialUSB.println(“Hello, world!”);
delay(500);
}