We have very liitte informatin from your post. How much sun is it getting? Temperatures? Humidy? Watering? I would guess under watering. Citrus like to go somewhat dry but will show wilt if too dry.

How long have you had this plant? If for several years, when has it last been repotted, perhaps root pruned? I’d like to see more pictures, to include a shot of the top of the potting medium (to see what your potting medium looks like), a close up of the leaves, etc.