Change Story

I hired a story coach to help me as I attempt writing my first novel. She asked me to send her the short synopsis of my book and gave me a feedback that there is not enough of a story there. She then asked me if I have other ideas and I told her I have two more but that I’ve been trying to develop this particular story for six months now.
She gave me her professional opinion that it won’t work and that I should invest my time in another story.

In one of your workshops you mentioned that you don’t allow your coaches to change their niche. Do you think I should insist on writing this story no matter what or take her professional advice?