Thanks for your question! This looks like a Yucca Elephantipes. These desert plants like a bright indirect sunlight and infrequent watering, so it sounds like you're doing things right. In terms of the watering, you might try monitoring how dry it is and watering only whenever the top 1/4 of the soil is dried out. Even with infrequent watering it may be possible overwater. From the photo it looks like it may be in a potting mix that is mostly peat based, and it may be retaining water longer than a more free draining potting mix. 

Another possibility is that it could be rootbound, and it may need to be repotted into a slightly bigger pot (about an inch bigger around the whole plant). If you do this, then use a potting soil for cactus since that will provide the kind of free draining soil that this plant likes. If you have had this plant in the same pot for a year, the timing would be right for it to need to be potted up to a bigger pot size. There are some helpful directions for repotting houesplants here: https://wayne.ces.ncsu.edu/2022/04/repotting-houseplants

One other possibility is that it could just be browning and dropping leaves because it's winter and is getting less sunlight than it does in the warmer months. 

Hopefully these solutions help your yucca return to its previous healthy state.