Ceiling Fan Canopy Safe Ceiling Fan Install?

Safe ceiling fan install? - ceiling fan canopy

I installed a ceiling fan, but the new junction box flush with the ceiling (ie, fixed), which means that the upper deck of the ceiling fan actually on the ceiling (about 1 / 2 cm -1). I am not with the hole that I can cover it relates to a ceiling mirror, but it seems that the vibrations would be a big problem in this way. I have not succeeded in the extensors of the junction box (or junction see box above), is also rated the fan junction box is on a suspension bar, the inverted U-shaped ends. It was a race to the bar, so I prefer to stick to the bar and replace the box if possible. Thanks for the advice and suggestions.