
Certified GKH Gardening Expert
I see that it is in a pot within a pot. When watering, the inside pot should be taken out, watered, and drained before returning it. In the photo, it looks like the plant may be overwatered. Even though it prefers moist soil, it doesn't tolerate saturated soil. Let it dry out between waterings and see if that helps. (If the soil is very wet, it wouldn't hurt to repot it in fresh, dry potting mix.) The article below gives more care tips that should help.
https://www.gardeningknowhow.com/houseplants/birds-nest-fern/birds-nest-fern-care.htm