# Flask app wont start

**URL:** <https://forum.freecodecamp.org/t/flask-app-wont-start/276041>\
**Category:** General\
**Created:** [May 8, 2019, 1:07am UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041 "2019-05-08T01:07:47Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![alkapwn3d](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/alkapwn3d/32/92787_2.png) [@alkapwn3d](https://forum.freecodecamp.org/u/alkapwn3d)\
**Post date:** [May 8, 2019, 1:07am UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/1 "2019-05-08T01:07:47Z")

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**Error**  
`flask.cli.NoAppException: Failed to find Flask application or factory in module "hello". Use "FLASK_APP=hello:name to specify one.`

[http://flask.pocoo.org/](http://flask.pocoo.org/) - I followed these instructions

Anyone have this problem before?

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**Author:** ![brandon\_wallace](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/brandon_wallace/32/198757_2.png) [@brandon\_wallace](https://forum.freecodecamp.org/u/brandon_wallace)\
**Post date:** [May 8, 2019, 1:24am UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/2 "2019-05-08T01:24:28Z")

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@alkapwn3d We need to see your code. It looks like it is looking for a file or module that is not there. Check carefully for syntax errors.

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**Author:** ![alkapwn3d](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/alkapwn3d/32/92787_2.png) [@alkapwn3d](https://forum.freecodecamp.org/u/alkapwn3d)\
**Post date:** [May 8, 2019, 1:35am UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/3 "2019-05-08T01:35:09Z")

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click the link and see the instructions. thats exactly what i have and did

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**Author:** ![reyesvicente](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/reyesvicente/32/84136_2.png) [@reyesvicente](https://forum.freecodecamp.org/u/reyesvicente)\
**Post date:** [May 8, 2019, 4:46pm UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/4 "2019-05-08T16:46:19Z")

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Can we see your code?

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**Author:** ![reyesvicente](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/reyesvicente/32/84136_2.png) [@reyesvicente](https://forum.freecodecamp.org/u/reyesvicente)\
**Post date:** [May 9, 2019, 8:03am UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/5 "2019-05-09T08:03:10Z")

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Go to the folder where app.py is present and run python app.py

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**Author:** ![unicornxoxo1919](https://avatars.discourse-cdn.com/v4/letter/u/b19c9b/32.png) [@unicornxoxo1919](https://forum.freecodecamp.org/u/unicornxoxo1919)\
**Post date:** [May 27, 2019, 9:39pm UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/6 "2019-05-27T21:39:41Z")

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i think you did not set the environment variable of your flask app. flask doesn’t know which file to run ?

specify FLASK\_APP=“app.py”

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**Author:** ![ILM](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/ilm/32/363239_2.png) [@ILM](https://forum.freecodecamp.org/u/ILM)\
**Post date:** [January 16, 2021, 11:35am UTC](https://forum.freecodecamp.org/t/flask-app-wont-start/276041/7 "2021-01-16T11:35:59Z")

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Closed on January 16, 2021, 11:35am UTC