Hi Rosita, Are you letting your cake settle after you’ve torted, filled, and stacked it? The cracks might be a sign of settling it. I always chill my cakes before icing/ganaching in the fridge with a plastic wrapped cardboard on top and a 1 lb block of butter (or 2 if its a large cake). I do this anywhere from 30 minutes to a few hours depending on how much time I have. Good luck!