Brown leaves on palm trees generally indicate a problem with how much water or sunlight the tree is receiving. This is true for both indoor and outdoor palm trees.
When palm trees are overwatered, leaves are likely to turn brown or yellow and to fall off the palm. However, underwatering can also result in brown leaves. Palm trees should be watered whenever the soil is slightly dry; they require less water during the winter. Young palm trees or those grown indoors need to be acclimatized to direct sunlight. Too much sun received too quickly can cause leaves to become sunburnt and brown. Indoor palm trees should receive filtered light whenever possible.