Is Node-Red throwing an error in the console when you attempt to start it? In the first post the last screen shot appeared to throw the error port already in use.
When the USB modem is connected to your computer does the USB LED turn on solid? Also do you see a new port listed in /dev/tty*? If not it’s possible you’ll need to install a driver. Please let me know which Modem you are connecting to the computer I want to make sure it’s a USB modem and not a Mega Modem, you can just provide a photo of the modem connected to the computer with the lid removed.
As a quick response for your questions:
The USB modem is connected to a computer with Ubuntu OS
USB LED status: the devices are setup in a remote location (another country). I will get this later
Is the port listed: Yes. see screenshots.
Instal Driver: Can you share the driver for ubuntu?
Modem details: I can get them from the Order under our account: Industrial IoT Wireless to USB Modem. If you still need the photo of the modem, I can send our technician to take a photo for the modem with the lid removed.
If the Modem is mounting to the system’s /dev directory then there is no need to install the driver.
This is most likely a permissions error on the /dev/ttyUSB0 serial port. More than likely on your system the permission group for the port is Dialout. You may need to add node-red to the dialout group. You can take a look at a GitHub issue here in reference to that: