I started my application which is listening to 0.0.0.0:8080 (host and port from environment variables), pushed “Preview” button and it said: “No application seems to be running here!”. Then I wrote:
$ wget -O - http://0.0.0.0:8080
It worked and successfully printed my page, so I think there may be C9 bug.
I am sorry, there are a lot of topics like this, and I am opening yet another. However, I did not find answer to my question in other topics. Everybody say something like: “I logged off, waited a few hours/days and it is working now!”. I tried to do the same, but it did not worked for me.
I use Ruby, Thin, Sinatra.