My chili plant flowers then the flower and stem dies and drops off. what am i doing wrong?

Probably over-watering and insufficient light levels; they originate from a sunny, hotter and drier climate than the UK (assume that's where you are). You need to try and replicate those conditions for real success.

FlowersBirthday FlowersSympathy FlowersAre you growing them indoors or outside? Chillies are semi- to tropical plants and do not like cold night temperatures. They also need humid air when fruiting. They are also susceptible to disease. They are not easy to grow in temperate countries unless you have experience and a greenhouse.Shoes