At the quantum level gravity is not explained properly yet. My favorite rant is from Heisenberg in his autobiography.

But even on the astronomic level GR leaves the dark matter hole, which is a non-satisfactory explanation to many. Elegant yes, but certainly not proper.

General Relativity cannot be (yet) quantised in a predictive way.

GR only works at large scales. It is still unclear how gravity at quantum scales should be modeled.