twrp – Flash recovery Lg Aristo 2 Fastboot – FAILED (remote: 'unknown command')

I've recently tried to make twrp blink on my Lg Aristo 2, when I launched the code under OEM Unlock, a device came out with the same message "FAILED (remote: unknown command & ### 39;). "
I started backing up my phone and he came to a setup screen, I set up my phone and he said that he was unlocked OEM. When I try to flash a custom recovery, or execute a command with fastboot at the beginning, I get "FAILED (remote: unknown command") and it does not work not. May I have help please?