heroku Heroku Error Codes H15 - Idle connection
Example
The dyno did not send a full response and was terminated due to 55 seconds of inactivity. For example, the response indicated a Content-Length of 50 bytes which were not sent in time.
2010-10-06T21:51:37-07:00 heroku[router]: at=error code=H15 desc="Idle connection" method=GET path="/" host=myapp.herokuapp.com fwd=17.17.17.17 dyno=web.1 connect=1ms service=55449ms status=503 bytes=18
