@martijnroks guess so,
in the Arduino IDE, what port does it say it’s connected to?
also put printArray(Serial.list()); before:
String portName = Serial.list() ;
to see all available COMs and which index is which port. when you know which port the Arduino is connected to, connect processing to this port too with the listed index from printArray(Serial.list());.
also on another note, on the Arduino side you could easily just put Serial.println(x + ‘,’ + y);
on one line instead of 4 different lines.