Error: Arduino Serial port closed when connecting to arduino Uno

I got this error after starting node-red, deploying a flow where I send true on the payload of a message to arduino Digital pin 9 and then changing the pin to 12 and deploying again.
I'm on an Ubuntu 22.04 Virtual Machine.
With Node 20.9.0, NPM 10.1.0 and Python 3.10.12
Thanks in advance for your help.

Imagine you don’t know your setup, then reread what you posted and ask yourself if you could help yourself.

My guess is you wouldn’t be able to. You need to provide more information.

Edited. Thanks for answering.

What version of NR are you running?
You say you send true on the payload of a message how are you sending it?
how are you changing the pin from 9 to 12?
What is running on the Arduino?
How are you connecting the Arduino to the virtual machine?

Node Red version: 3.1.0

I send it through an Inject node, with the following settings:

When the program executed, I clicked on the button of the inject node to send the message.

I change it from 9 to 12 through the settings of the Arduino Out node and then deploying.

The "Firmata Standard" example is what is running on the Arduino.

I connected it by going to the settings of the virtual machine on VirtualBox, clicking in that small usb icon with a "+" sign, selecting the only option which had the words "Arduino Uno", clicking ok and then adding my user to dialout in Ubunto.

Which node-red are you using to send the true to the arduino ?
Please export your flow and attach it to a reply

In order to make code readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)

   code goes here 

You can edit and correct your post by clicking the pencil :pencil2: icon.

See this post for more details - How to share code or flow json

Do you have the latest node-red-node-serialport installed ?
The node-red-node-arduino node requires a (very) old version of the underlying serialport library and the newer node-red-node-serialport node causes a conflict with it so currently you can't use both at the same time.

I have a workaround/fix but it needs node16 so will have to wait until we release node-red v4.

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