# Error while deploying on Heroku
**URL:** https://community.plotly.com/t/error-while-deploying-on-heroku/25072
**Category:** Dash Python
**Created:** [June 26, 2019, 7:35am UTC](https://community.plotly.com/t/error-while-deploying-on-heroku/25072 "2019-06-26T07:35:39Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@dave1](https://community.plotly.com/u/dave1)
#### Post date: [June 26, 2019, 7:35am UTC](https://community.plotly.com/t/error-while-deploying-on-heroku/25072/1 "2019-06-26T07:35:39Z")
Hi. I am making a Dash app and using Heroku for deployment. I’ve been trying to deploy it for so long but it shows the following error.
2019-06-26T07:24:54.619101+00:00 app[web.1]: Traceback (most recent call last):
2019-06-26T07:24:54.619129+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/arbiter.py”, line 583, in spawn\_worker
2019-06-26T07:24:54.619132+00:00 app[web.1]: worker.init\_process()
2019-06-26T07:24:54.619134+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/workers/base.py”, line 129, in init\_process
2019-06-26T07:24:54.619136+00:00 app[web.1]: self.load\_wsgi()
2019-06-26T07:24:54.619138+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/workers/base.py”, line 138, in load\_wsgi
2019-06-26T07:24:54.619140+00:00 app[web.1]: self.wsgi = self.app.wsgi()
2019-06-26T07:24:54.619142+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/app/base.py”, line 67, in wsgi
2019-06-26T07:24:54.619145+00:00 app[web.1]: self.callable = self.load()
2019-06-26T07:24:54.619146+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py”, line 52, in load
2019-06-26T07:24:54.619148+00:00 app[web.1]: return self.load\_wsgiapp()
2019-06-26T07:24:54.619150+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py”, line 41, in load\_wsgiapp
2019-06-26T07:24:54.619152+00:00 app[web.1]: return util.import\_app(self.app\_uri)
2019-06-26T07:24:54.619154+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/util.py”, line 350, in import\_app
2019-06-26T07:24:54.619156+00:00 app[web.1]: **import** (module)
2019-06-26T07:24:54.619165+00:00 app[web.1]: ModuleNotFoundError: No module named ‘app’
2019-06-26T07:24:54.619356+00:00 app[web.1]: [2019-06-26 07:24:54 +0000] [10] [INFO] Worker exiting (pid: 10)
2019-06-26T07:24:54.678044+00:00 app[web.1]: [2019-06-26 07:24:54 +0000] [4] [INFO] Shutting down: Master
2019-06-26T07:24:54.678274+00:00 app[web.1]: [2019-06-26 07:24:54 +0000] [4] [INFO] Reason: Worker failed to boot.
2019-06-26T07:25:00.000000+00:00 app[api]: Build succeeded
2019-06-26T07:25:18.401063+00:00 heroku[web.1]: Starting process with command `gunicorn app:server`
2019-06-26T07:25:20.645695+00:00 heroku[web.1]: State changed from starting to crashed
2019-06-26T07:25:20.624583+00:00 heroku[web.1]: Process exited with status 3
2019-06-26T07:25:20.470276+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [4] [INFO] Starting gunicorn 19.9.0
2019-06-26T07:25:20.470989+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [4] [INFO] Listening at: [http://0.0.0.0:59597](http://0.0.0.0:59597) (4)
2019-06-26T07:25:20.471166+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [4] [INFO] Using worker: sync
2019-06-26T07:25:20.475944+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [10] [INFO] Booting worker with pid: 10
2019-06-26T07:25:20.481633+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [10] [ERROR] Exception in worker process
2019-06-26T07:25:20.481636+00:00 app[web.1]: Traceback (most recent call last):
2019-06-26T07:25:20.481639+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/arbiter.py”, line 583, in spawn\_worker
2019-06-26T07:25:20.481641+00:00 app[web.1]: worker.init\_process()
2019-06-26T07:25:20.481643+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/workers/base.py”, line 129, in init\_process
2019-06-26T07:25:20.481645+00:00 app[web.1]: self.load\_wsgi()
2019-06-26T07:25:20.481647+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/workers/base.py”, line 138, in load\_wsgi
2019-06-26T07:25:20.481649+00:00 app[web.1]: self.wsgi = self.app.wsgi()
2019-06-26T07:25:20.481652+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/app/base.py”, line 67, in wsgi
2019-06-26T07:25:20.481654+00:00 app[web.1]: self.callable = self.load()
2019-06-26T07:25:20.481656+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py”, line 52, in load
2019-06-26T07:25:20.481658+00:00 app[web.1]: return self.load\_wsgiapp()
2019-06-26T07:25:20.481663+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py”, line 41, in load\_wsgiapp
2019-06-26T07:25:20.481665+00:00 app[web.1]: return util.import\_app(self.app\_uri)
2019-06-26T07:25:20.481667+00:00 app[web.1]: File “/app/.heroku/python/lib/python3.6/site-packages/gunicorn/util.py”, line 350, in import\_app
2019-06-26T07:25:20.481669+00:00 app[web.1]: **import** (module)
2019-06-26T07:25:20.481710+00:00 app[web.1]: ModuleNotFoundError: No module named ‘app’
2019-06-26T07:25:20.481814+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [10] [INFO] Worker exiting (pid: 10)
2019-06-26T07:25:20.518855+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [4] [INFO] Shutting down: Master
2019-06-26T07:25:20.519005+00:00 app[web.1]: [2019-06-26 07:25:20 +0000] [4] [INFO] Reason: Worker failed to boot.
2019-06-26T07:26:50.184549+00:00 heroku[router]: at=error code=H10 desc=“App crashed” method=GET path="/" [host=app-is-new.herokuapp.com](http://host=app-is-new.herokuapp.com) request\_id=efcf24fb-6b6c-4911-883e-ea98797e4543 fwd=“115.113.127.77” dyno= connect= service= status=503 bytes= protocol=http
2019-06-26T07:27:32.897277+00:00 heroku[router]: at=error code=H10 desc=“App crashed” method=GET path="/" [host=app-is-new.herokuapp.com](http://host=app-is-new.herokuapp.com) request\_id=eade51d5-8769-4846-b5d8-6c362215455a fwd=“115.113.127.77” dyno= connect= service= status=503 bytes= protocol=http
It says for no module named ‘app’ but I haven’t used app anywhere and it’s my app that is named app.py
Can anyone help me out? Thank you! 🙂
---
### Author:  [@qdumont](https://community.plotly.com/u/qdumont)
#### Post date: [June 26, 2019, 7:39am UTC](https://community.plotly.com/t/error-while-deploying-on-heroku/25072/2 "2019-06-26T07:39:43Z")
Is gunicorn in your requirements file? Often when i use :
```
pip freeze > requirements.txt
```
gunicorn is not inside, so heroku does not install and that might be the problem.
---
### Author:  [@dave1](https://community.plotly.com/u/dave1)
#### Post date: [June 26, 2019, 8:07am UTC](https://community.plotly.com/t/error-while-deploying-on-heroku/25072/3 "2019-06-26T08:07:09Z")
Hi. Thank you for your reply.
Yes. Gunicorn is in my requirements file.