I successfully deployed my first app following the the instructions on http://shiny.rstudio.com/articles/shinyapps.html.
I then successfully deployed my second app.
I decided to make some changes to my first application. I archived and deleted the application, created a new R file of the app and then tried to deploy it. Everything works well and I see the following message in the "Deploy" window:
Application successfully deployed to https://hessamss2.shinyapps.io/icu_infection
However, when the app page pops up, what I see is the following error message:
"ERROR: You must register an account using setAccountInfo prior to proceeding."