I see two or three issues, related.
Is it potted in pure coco coir? Are you fertilizing? What is that container — size? Drains holes?
Looks to me like lack of nutrients. Get it into regular potting soil, feed it a liquid fertilizer, either for bloom & fruit or specifically for tomatoes. And tell us about that pot.
Yes, do not mist. Keep the soil uniformly moist at all times, not soggy. And it should be getting as much sun as possible.
