I think what Jack meant to say was “It’s not what you write, but how you write it.” Jack should take some English classes if you ask me.
Okay, enough bad jokes. This tiny little quote holds a lot of weight! If a story isn’t working for you, it might not be what you’re trying to say. It could be how you’re saying it. Maybe you need to throw a character in, or change the way you describe something. Maybe you need to take some of the description out of there is too much, or add a bit of dialogue to get a better feel for the character. There are many ways to mix things up! Think about why the story isn’t working, and try a few things and see what you like best.
The story is inside of you. You just have to let it out.