You need to physically move her to the new litter box location. At the moment, she does not perceive that as being an option. Remember that rabbit’s are inclined to be litterbox trained because they are inclined to choose a place to go, and go there consistently. Your rabbit picked up pooping/peeing in her old cage’s location, not in a litter box, so although her new cage may have a litterbox, for her, that doesn’t really mean anything. Just as she had learned to adopt the old cage area as the toilet, you’ll need to guide her that the toilet is somewhere else now. Can you create an xpen around the new cage, sit in it, and monitor her for training sessions? Each time she goes, bring her to the new box.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.