Difficulty to up nodejs application on heroku

Hello,

I currently have a nodejs (webhook) solution that I would like to put on heroku.
I have the tutorial to put it however when I deploy there is an error that I do not understand

Application : https://callapiserver.herokuapp.com/

2021-08-27T13:10:43.720513+00:00 heroku[web.1]: State changed from starting to crashed
2021-08-27T13:10:43.726850+00:00 heroku[web.1]: State changed from crashed to starting
2021-08-27T13:10:46.426178+00:00 heroku[web.1]: Starting process with command `npm start`
2021-08-27T13:10:48.381784+00:00 heroku[web.1]: Process exited with status 1
2021-08-27T13:10:48.336549+00:00 app[web.1]: npm ERR! missing script: start
2021-08-27T13:10:48.343589+00:00 app[web.1]:
2021-08-27T13:10:48.343726+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2021-08-27T13:10:48.343771+00:00 app[web.1]: npm ERR! /app/.npm/_logs/2021-08-27T13_10_48_337Z-debug.log
2021-08-27T13:10:48.441156+00:00 heroku[web.1]: State changed from starting to crashed
2021-08-27T13:10:57.396469+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=callapiserver.herokuapp.com request_id=749048d2-65b5-4151-a425-c65a7e725bb6 fwd="191.101.31.43" dyno= connect= service= status=503 bytes= protocol=https
2021-08-27T13:10:57.771225+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=callapiserver.herokuapp.com request_id=4579e477-7ff1-4288-b995-d77b8e7caca7 fwd="191.101.31.43" dyno= connect= service= status=503 bytes= protocol=https

I need help
Possibility to come in anydesk.

Thanks