Issue connecting to arduino with mcreator link

Big problem that I'm desperate to solve. Any help is highly appreciated.

Running MCreator Link 1.3 for 1.16.5.

I'm having issues connecting to the arduino (Mega 2560)

I use the MCreator Link menu to connect to the arduino. "Connected" I run /link device, arduino is detected, everything normal here.

I run /link digitalwrite 13 1, Nothing happens.

I run /link device, "No device connected!"

The arduino seems to disconnect once I issue a command that does anything with the arduino. I have tried this on a different computer, same versions, and everything actually works on that computer, unfortunately I rarely have access to that one.