I am not sure. It happens to me sometimes. But when I first submit an article, I make sure the language is correct, no mistakes in the grammer, as little typos as possible, and the structure is balanced, there is a beginning, a middle and an end if you like. Of course writing Hub articles is not really like articles we used to do back in school, but they have to keep the reader engaged, flowing from one paragraph to another. If the info is insufficient add more meat, think about what you want to put forward, visualize and construct the Hub in your mind and then begin to write it down within a logical framework, like the above. Hopegully, it will work. Pick up and nice headline.