Eggplant and tomatoes
My eggplant produces flowers but instead of producing fruit, the flower and stems fall off. I have it in miracle gro soil. My tomatoes are about 6 ft tall and have made one flower but no tomatoes.
It is most likely a pollination issue. The plant will discard any flowers that are not pollinated. Has it been very humid where you live? This would do it. Most of the country has been suffering from extreme heat and humidity this season.
These articles will help: https://www.gardeningknowhow.com/edible/vegetables/eggplant/what-to-do-for-eggplant-blossoms-drying-out-and-falling-off.htm