Minecraft: Villager does not accept job?

I play Minecraft in 1.16.4 and here is a villager without a job, but he won't accept him. How so? He's supposed to be a farmer, so I put this thing up for him, but nothing happens. I've already re-logged.

It sometimes takes a while or is sometimes strangely buggy if it doesn't work out try someone else or just wait. I also tried to build an entire village, afterwards I was too excited and if you give up then he suddenly becomes a farmer 😂