Right now, I'm working with my second customer, however, this time I'm working on a Fitness app. The ads and ad sets have been made, but I'm continuously getting this error that the app is not linked to my ad account. The picture has been attached. Because of this, I cannot start the ads, even though the developer is saying that the app is reading all events including installs and sign-ups. What can be the problem here? I have attached some pictures.