Tomato blossom drop
Why are my strong-looking, beautiful tomato blossoms falling off before producing?
Certified GKH Gardening Expert
It is most likely a pollination issue. The plant will discard any flowers that are not pollinated. Most of the country has been suffering from extreme heat and humidity this season, and this would do it.
I believe your problem is excessive heat. Tomatoes will not set above 90 degrees. The only other reason would be disease.