First, there is the chirality problem. Chirality is determined by the sense of spin. However, only the former are observed in nature. Second, we again have a cosmological problem. The seven extra dimensions must form a small compact structure which induces the four dimensions of spacetime to became highly curved as well.
Astronomical observations suggest zero or close to zero space-time curvature.
One may add a cosmological constant to solve this but such freedom to adjust the underlying equations is not present in 11 dimensional supergravity. A possiblity to subdue this issue is through superstring theory. These must be instead constructed in 10 dimensional spacetime and in superstring theory infinite quantities are absent.