Replace Serial with Serial0
Because the DigiX uses Native USB Serial instead of the second programming port the Due has, but we still want to make it compatible with most sketches which assume the serial monitor is on Serial not SerialUSB - we changed it as follows:
Due DigiX
Serial Serial0
SerialUSB Serial or SerialUSB
Serial1 Serial1
Serial2 Serial2
You can also just select the Due as the board instead of the DigiX and it will work just fine with the Due mappings - WiFi and other DigiX specific features may not work though.