Why does your rabbit not like carrots?

If your rabbit usually likes carrots, and suddenly won't eat them, she is probably ill. If, in all other ways, your rabbit is fine (eating, drinking, peeing, pooping, moving around, and socializing/playing like normal), you should keep a close eye on her and consult your regular "rabbit-savvy" vet as soon as possible -- depending on the details of your situation, the vet may suggest you go in for a visit.

If your rabbit isn't eating anything, isn't using the toilet, and/or is showing signs of pain (awkward posture, loud irregular tooth grinding, depression, lethargy, hiding, etc.), this is an emergency and you need to bring your rabbit to a vet immediately for subcutaneous fluids and pain and gut motility medication at least, to tide your bunny over until your regular vet is available.

If your rabbit has never liked carrots, and he's been to a vet and is known to be healthy, then he probably just doesn't like carrots for individual reasons. Rabbits are subject to personal taste just like humans are!