Convection Oven Why Should I Not Use Oven Cleaner On A Convection Oven?

Why should I not use oven cleaner on a convection oven? - convection oven

I just spray Easy Off on my convection oven. I thought I read all the directions. Then I read this should not be used in ovens. Does anyone know why? I continue a cycle of self-cleaning, but the smoke days. Have I damaged my oven by spraying, when he said that I did not?