Why are my California wonder pepper plants rotting on the plant before turning red?

Question

Niagara on the lake planting zone.

Answer 1

There are a couple possibilities, but without additional detail I will provide links to these articles that will help you identify the problem:
https://www.gardeningknowhow.com/edible/vegetables/pepper/common-pepper-plant-problems.htm

https://www.gardeningknowhow.com/edible/vegetables/pepper/pepper-blossom-end-rot.htm