My villager his trade is not locked but I can't do the trade [closed]

So I have a Librarian Villager and the first trade is the mending book and the second one is the bookshelf. Its not only this one but also the other villagers. The problem i when I give him emeralds he always gives me the bookshelf trade. Even when I press on the book trade it stays stuck on the bookshelf trade. I tried leveling him up one level. And I am able to do all the trade. Only the book trade seems to be stuck. (He is not sold out)

Look closer on the 'price' side of the enchanted book trade. There's a certain amount of emeralds - and a regular book. You have two slots for the 'paid' items. Put the emeralds in the first one and a plain unenchanted book in the other. Emeralds alone aren't enough for these trades.

Plain unenchanted books can be obtained in these ways:

• crafting 3 paper and 1 leather,
• breaking a bookshelf with a non-silktouch tool (you get 3 books)
• disenchanting an unwanted enchanted book in the grindstone