Lightburn don't talk with my machine

Hi.

I forget to say, but I did it. I did the command “sudo adduser…”.

I tried the next solution, like as Peter Smith wrote, but it doesn’t work too.

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When I launch Lighburn, the laser turn on and suddenly turn off, like always happened. But, after this, nothing happens.
On the Lightburn console, I receive this message:

Waiting for connection…
Grbl 1.1h [‘$’ for help]
ok
[VER:1.1h.20190825:]
[OPT:V,15,128]
Target buffer size found
ok
Homing
error:5
Homing cycle is not enabled in your Grbl settings.