It sounds like nitrogen burn and overwatering. I would recommend composting any manure before adding it to soil, and making sure to take a soil sample before doing so as well. If there is no lack of nitrogen in the soil, then adding will cause there to be too much in the soil. This will burn plants.
Also, it is best to water only when the soil is completely dry down to about 2 inches deep. Keeping the soil too wet for too long will cause infection, and cause the soil to have a very low oxygen content.
This article will give you information on the proper care of corn: https://www.gardeningknowhow.com/edible/vegetables/corn/grow-sweet-corn.htm