Space saver toaster oven keeps falling`

After happily coexisting with us for several years our black and decker under counter oven has become fearful of heights, and now plops off the brackett and to the ground whenevery it wishes. It is easy to put up, so easy that I do it several times a day. I have a feeling I am missing some very redumentary step in mounting this. Any advice?

How is it held up?
Sounds like the bracket may be loose, with enough play to allow the toaster to slip out.