I can't start/configure the the addon, since it requires a 'device' which I am unable to select, since none is shown:

When I try to use the YAML configuration and just enter any device, I get different validation errors.
When using /dev/null it says the value does not match the filter:

When I try with "tty" it says the device does not exist.

I also tried /dev/ttyS0 to /dev/ttyS9 and /dev/USB0 to /dev/USB9 but all are giving the same error.
Any suggestions how to solve this?