Your floor material also seems lit strangely in the content browser, which seems to indicate an issue with the normals in the material instead of an issue with the light. Try looking at those first.
Your skylight is set to “Captured Scene” mode. In this mode it will take the color of your environment to light the scene. This does require you to actually have something in the environment such as a skybox or atmosphere to get any light. Try adding one of those or switching to cubemap mode to fix this.