Q.Bottom stems falling off pepper plants
3 different types of pepper plants planted in tall containers beds. Bottom stems falling off all plants. Need to find out cause.

This could be lack of water or uneven watering, excess fertilizer, pests or disease issues.
These articles will help you pinpoint the issues.
https://www.gardeningknowhow.com/edible/vegetables/pepper/growing-peppers-container.htm
https://www.gardeningknowhow.com/edible/vegetables/pepper/common-pepper-plant-problems.htm
https://www.gardeningknowhow.com/edible/vegetables/pepper/pepper-problems.htm