R's shiny app goes grey when deployed, works fine locally
I don't know what exactly your app should be doing, but it seems to work fine for me as well. As far as I can tell your log doesn't show any errors either.
Might this be a timing issue? After 15 minutes of inactivity your app is put to sleep and when you surpass your active hours with a free account your app will not work either. Checkout the shinyapps user guide section 3.3 http://docs.rstudio.com/shinyapps.io/applications.html#application-life-cycle for more details
After the time out I see a greyed out version of the app screen with a message "Disconnected from the server" and a "reload" button. Is that how it looks to you?
I don't know how this looks when you use up all your active hours and I'm not going to try. You have to test this yourself.