I just want share that I was having the same problem using home assistant core installed from the arch linux repositories. It turns out that the permissions on the dongle device file (/dev/USB0) were rw-rw---- with user root, and group uucp. The systemd file installed creates a hass user, but that user doesn’t have permissions to access the device. In order to give access to the hass user, one can use systemctl edit --full home-assistant.service and add the line SupplementaryGroups=uucp, which will add the hass user to the uucp group. Then, after a systemctl daemon-reload and systemctl restart home-assistant.service you should be up and running.
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