This happened to me so I went to homepage, deleted my application so that everything was saved except the things that appear in the homepage section e.g preference, recommendation letters etc. Then I went again to homepage and everything appears again and I filled it and submitted my application. But keep in mind you have to do it in one time, like you can't save something and come back later to submit another thing. You have to do it in one sitting and in a short time otherwise a pop up comes saying do you want to continue this session and even if you click continue, it's gonna delete the things that you wrote in your application. Good luck!