Can't launch expert mode

[Collapsed-TI]

LG CX 4.50.51. I get this error:

root@LGwebOSTV:~# luna-send -n 1 luna://lol.downgr8.service/fakeusb/getStatus '{}'
{"returnValue":true,"isAttached":true,"isAuthenticated":true}

root@LGwebOSTV:~# luna-send -n 1 'luna://com.webos.service.update/setExpertMode' '{"mode":true}'
{ "returnValue": false, "errorCode": -3, "errorText": "Error has occurred in the process" }