Can't say for sure, but overwatering is very common. Let the media (soil, coco, whatever) dry out well before watering. Let the roots develop and go from there. goodluck
I would air that mix out with some perlite. That way it will drain faster. They don't look too bad though. Just wait until the pots are light from the water getting used or evaporating before you water more. No nutes for awhile.