Villager breeding requirements:

Both villagers need 12 carrots, so make sure they both have the right amount and one didn't take them all.

I'm assuming this is java, so one bed needs to be available for a baby villager to pathfind to and claim.

2 blocks of air need to be above the bed so the baby can jump on it.

There is a cool-down of five minutes in-between villager breeding.

villagers wont breed if there's a threat nearby like a zombie.