Q.My String Beans Have Blooms But Do Not Produce, Do They Need A Specific Fertilizer?
They produce once, but then they don’t produce. They are watered either every other day, or every day, depending on the temperature.
Certified GKH Gardening Expert
You don't mention whether there are new flowers that don't produce, or if the plant stops producing entirely. Also, each plant is programmed to produce a certain number of beans, so if you've harvested a healthy crop, that may be all you're going to get from that plant.
If you scroll down on this link a bit to our Gardening Know How articles, you'll see a series of pieces about bean plants - maybe these will help you identify the problem: https://www.gardeningknowhow.com/search?q=bean%20plants%20not%20producing