/dev/ttyACM0 permission denied on Ubuntu 24.04

Question 1

I'm struggling to access an MCU connected to the USB and presented as a serial port: /dev/ttyACM0. What worked well in Ubuntu 22.04 does not work in 24.04. Whenever I connect the device, the only way to have it access is to chmod 666 it, but that works only temporarily.

The user I'm working on is already added to the dialout group, and ls -l /dev/ttyACM0 returns: crw-rw---- 1 root dialout 166, 0 Oct 25 15:33 /dev/ttyACM0 , so as I can understand it, it is the root who has r/w and any dialout group member. Am I missing anything here to configure/add?

Edit: The driver seems to be correct so that is not the case of invalid UDEV rule triggered:

[21856.363341] usb 3-6: new full-speed USB device number 6 using xhci_hcd
[21856.761217] usb 3-6: New USB device found, idVendor=2e8a, idProduct=0005, bcdDevice= 1.00
[21856.761236] usb 3-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[21856.761240] usb 3-6: Product: Board in FS mode
[21856.761244] usb 3-6: Manufacturer: MicroPython
[21856.761247] usb 3-6: SerialNumber: e6614c311b7f8c38
[21857.365083] cdc_acm 3-6:1.0: ttyACM0: USB ACM device
[21857.365219] usbcore: registered new interface driver cdc_acm
[21857.365225] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

Question 2

You can solve the problem by adding yourself to the right group. As per your screenshot, the right group in your case is dialout:

sudo usermod -a -G dialout YOUR_USER_NAME

Important: You may need to log out and back in (or restart your machine) for your new permissions to take effect.