Enchanting

Hello.

I'm playing in a singleplayer world and I discovered that I cannot enchant my diamond leggings, boots and books in the enchanting table. I'm able to enchant my helmet, chestplate and the rest of the tools, but not those 3. Since i bought the game in 2019, I have never encountered this issue. I've searched the internet a few times to check if anyone has had this problem, but couldn't find anything useful. Also, I've attached 3 screenshots so you can see that no enchants appear in the table, no matter how many levels I have. 

Thank you!