Q.Eggplant flowers drop off, no fruit
I read the article on this, but it doesn’t help my situation. I am growing my eggplants indoors in hydroponic containers using the Kratky method. Lack of water is not an issue. The temperatures they are getting are usually between 66 and 70 indoors, and on nice days I take them out to the sunroom where it is between 65 and 80. On average they get anywhere from 3-6 hours of sunlight per day, plus artificial lighting when they are not exposed to the sun.
I am not sure why they don’t fruit, unless it’s too cold or not enough natural sunlight. I have tomato plants next to them and they are producing tomatoes. I hand pollinate everything by lightly tapping the flowers and/or stems, and brushing the flowers with q-tips, but nothing has worked. I had the same problem with the one grown outdoors last summer, but that was too much heat and not enough water, I’m sure. This is like the opposite problem.

Certified GKH Gardening Expert
It is unusual for eggplants, but it may be possible that they have thrips. They are a small pest that can attack the base of flowers and cause them to fall off. Normally an ornamental problem, but they could affect eggplant.
I would also check your nutrients. Just to be sure. If the balance is off, it could affect the flowers.