Hi I have been working with Unreal for 4 years now and I never saw this kind of problem.
So my character does not affected by the gravity scale. It has gravity but I cant increase it just decrease it. I have been tried everything, changing the gravity in the project settings ,changing the gravity in the world settings ,changing the gravity scale of the character. When I open a new project everything is fine, but I need my main project because I worked a lot on that.
Thanks for the help😀