I don't get it, I rolled back the changes that I've made, scanned again the port and it worked! I don't even restarted the pc, the port was responding!
Also yesterday, when a friend was trying to connect with port 21, appeared a message in the browser that said something like: "connection refused, for security the port is blocked" (something like that, I don't remember very well what he told me)
I typed the command "netstat -plant" and shows that the port 21 its listening
tcp6 0 0 :::21 :::* ESCUCHAR -
I really don't get it, if you have an idea of what happened please tell me because yesterday I was trying all day to make it work and now it just worked without headaches.