Just keep offering the same prey type than previously fed by the other owner and feed her in her enclosure.

If you can try to get info on how the animal was previously kept that might help (substrate, temps etc)

NO HANDLING

It can be seasonal, she might also have reach a plateau which often seems to happen around 900/1000 grams

I have had a female that size fasting for 9 months and barely loosing any weight so it happens, even more so in my opinion with older individual that are changing environment.

Remember as long as your husbandry is optimal the only thing you can really do is wait it out, your animal knows how to eat but she is just not ready to do so for you yet.