I have tried 3 different cables to connect to my Arduino due but this error keeps shows up. I'm new and not sure how to check the connection between the Arduino and my computer. Could my Arduino be broken?
Choose "NATIVE" port (not Programming Port).
Close the IDE.
Power-off and power-on your computer.
Start the IDE.
Open the sketch.
Close every Serial port on all IDE instances.
Try again.
This tells me you were using the other port and did not read the documentation. Your answer is probably in reading the Arduino Due documentation.