I agree with Ray.
Give it more water, but make sure the mix it is in can handle more water. Looks pretty okay on the pictures, but its hard to tell if there is a layer of dust/decayed matter in the bottom/middle when its dry. If the bottom looks like soil when you water- give it a repot. (Some shops sell mix that have small particles/dust in it- I try to remove that before using it when repotting)
If you get that sorted out, it might grow some new leaves. Sometimes it gets spots like that on the stem when loosing leaves. Yours doesnt look too bad, and it seems like the stem is pretty green. Sometimes its really yellow after loosing a leaf- usually more leaves die if you dont do anything fast. Yours is green, but need water.
And if you take it out of the pot, remove dead roots before potting back
Good luck with your plant
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