Ember Server build is successful but nothing shows up?

I am working for the first time with ember to build a web app for work. The specifics of the app aren't important though. What's important is that whenever I run ember server the build is successful, but then when I actually go to localhost:4200, nothing is there. The app was working earlier today as well, but when I generated a new model everything suddenly stopped working. I know this is a vague question and I'm sorry but I don't really know what to do so any advice would be helpful. Thanks.