Problem restoring SERIAL PORT "USED"

RouterOS Beginner Basics
1

I was working on a Routerboard 112.
I don’t remember what I’ve changed, but now the serial port doesn’t work correctly.
In the other Routerboard working fine I have Console → serial0 “used”
In the other one I have it “free”.
What’s wrong?

2

Make sure you disabled console,
system console set 0 disabled=yes