Why is villager breeding failing in a village?

The beds might not be close enough, or there might not be enough free space above them for the baby to jump.

[They] can produce a baby only if they have their own beds plus an available bed for the baby, and the beds have two empty blocks above them (there needs to be room for the baby to jump on the bed). If the population cap is met, or the beds are obstructed, angry particles appear above their heads (along with the heart particles), preventing them from mating.

Minecraft Gamepedia

Villagers are annoying. They use some odd methods of pathfinding that don’t always work.

1. Take 3 villagers FAR away from the original village
2. Build up a villager breeder (Tango Tek makes a good one on that)
3. Done!

I honestly would not use the original village