The browning could be caused by either lack of light or lack of water.

Ferns do not like direct sun. However, they do need bright indirect light for the entire day, not just a few hours. Light is far more important than humidity, so you may want to move it to a location where the light is better even if the humidity is not.

Ferns do not tolerate dry soil. Even a single lapse will cause delicate fronds to die. Always water it thoroughly as son as the surface of the soil feels barely damp or almost dry. Misting is not a substitute for watering the soil. Misting also does very little to increase humidity.