Well first of all rabbits can go a long time without eating, days even. So if you see your rabbit not eating one day don’t worry about it too much. However, if they do this for more than a day or so it is important to try and find out why. The first reason I would suspect would be dental problems, which can cause a lot of pain for the rabbit and make it difficult to eat. If you think your rabbit may have dental problems, you should take it to the vet for a check-up.

Another reason a rabbit may not be eating is if they are sick. This could be anything from a minor cold to something more serious like cancer. If you think your rabbit may be sick, you should take it to the vet for a check-up.
The last reason I can think of would be stress.
FAQS
1. Why won’t my rabbit eat?
There are a few reasons why a rabbit may not be eating, including dental problems, sickness, and stress.
2. What should I do if my rabbit isn’t eating?
If your rabbit isn’t eating for more than a day or so, you should take it to the vet for a check-up.
3. What can cause a rabbit to be stressed?
A rabbit can be stressed out for many reasons, including changes in its environment or routine.
4. How can I help my rabbit overcome stress?
If you think your rabbit is stressed, you should try to figure out what is causing the stress and see if you can fix it.
5. Why does my rabbit lick me?
This is due to your rabbit trying to groom you, which is normal behavior for rabbits.