The two likely possibilities are under-watering or poor drainage. Those may seem like opposite problems, but the end result to the plant is similar: desiccation, due either to a lack of water or root rot. Obviously under-watering is easier to fix, assuming the plant hasn't reached terminal desiccation, but you probably did try watering it.
Try repotting your Kangaroo Fern (Zealandia pustulata or similar) to examine the roots, soil and pot. Does that hanging pot have drainage holes? If not, that is likely the problem right there. Fresh soil and good drainage might improve the situation.
Also, you say the plant gets 'indirect' light, but the photo looks like deep shade away rom a window. Does it get more light at other times of the day?