Python Heroku未能找到应用程序应用程序错误

试图在Heroku上部署我的dash plotly仪表板，但出现以下错误：

2020-02-12T20:06:28.207580+00:00 heroku[web.1]: Starting process with command `gunicorn app:server`
2020-02-12T20:06:34.455328+00:00 heroku[web.1]: State changed from starting to up
2020-02-12T20:07:03.644528+00:00 app[web.1]: WORKER TIMEOUT (pid:10)
2020-02-12T20:07:04.647635+00:00 app[web.1]: WORKER TIMEOUT (pid:11)
2020-02-12T20:07:15.625829+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=GET path="/" host=kalinaxchallenge.herokuapp.com request_id=f2e2ef3e-c454-45fc-a5f0-f3e4fa1f59e1 fwd="197.221.254.77" dyno=web.1 connect=1ms service=30000ms status=503 bytes=0 protocol=https
2020-02-12T20:07:22.939065+00:00 app[web.1]: Failed to find application: 'app'
2020-02-12T20:07:28.354927+00:00 app[web.1]: Failed to find application: 'app'
2020-02-12T20:07:29.073920+00:00 heroku[web.1]: State changed from up to crashed
2020-02-12T20:07:28.813680+00:00 heroku[router]: at=error code=H13 desc="Connection closed without response" method=GET path="/favicon.ico" host=kalinaxchallenge.herokuapp.com request_id=7c1977fe-5495-4327-990f-68a433ed2269 fwd="197.221.254.77" dyno=web.1 connect=1ms service=11173ms status=503 bytes=0 protocol=https
2020-02-12T20:07:29.059525+00:00 heroku[web.1]: Process exited with status 4

我的文件：

web: gunicorn app:server 

和my requirements.txt

dash_core_components==1.5.1
dash==1.6.1
dash_html_components==1.0.2
pandas==0.25.2
plotly==4.2.1
gunicorn==19.0.0
numpy==1.17.4

还有我的app.py

if __name__ == '__main__':
        app.run_server(debug=True)

server = app.server

该应用程序在本地运行良好

似乎是一个奇怪的错误消息，至少对我来说是这样，因为这是我项目的结构

Procfile
app.json
app.py
dataset1
dataset2
requirements.txt

我不知道为什么它找不到应用程序，而它就在那里

---

注意：我没有名为app和deleted app.json的文件夹，我通过将此行添加到我的app.py解决了此问题

if __name__ == '__main__':
        app.run_server(debug=True)

server = app.server

---

如果将

requirements.txt

文件中的

gunicorn

升级到19.5.0，是否会遇到相同的问题？尝试过并升级到19.9.0@sumshyftw