It does not increase the trades of a villager

I wanted to market with a villager, (toolsmith) And ... I gave him what he asked for (Specifically 21 charcoal) and he gave me 1 emerald.

So far so good, but when I leave the menu of trade, it does not increase the options to trade more things.
So I always have to give it the same, without any change.

(The particles do not appear and are activated)