Why is heroku throwing an Application error?

Question

Heroku

I uploaded the application to heroku and
made a migration, but when I run it,
heroku open
it gives me an error

An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details. You can do this from the Heroku CLI with the command
heroku logs --tail

I checked the log and here is the answer

2020-08-30T14:00:17.263710+00:00 heroku [web.1]: Process exited with status 3 crashed
2020-08-30T14:00:18.000000+00:00 app[api]: Build succeeded
2020-08-30T14:01:05.766286+00:00 heroku[router]: at=error code=H10 desc="App crashed " method=GET path="/" host=sheltered-reef-33234.herokuapp.com request_id=0c2820c9-774c-4b3d-86c4-c53e2531f986 fwd="188.163.103.167" dyno= connect= service= status=503 bytes= protocol =https
2020-08-30T14:01:06.363461+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=sheltered-reef-33234 .herokuapp.com request_id=b16b581b-fce7-4dce-bfdd-8707f4ec2433 fwd="188.163.103.167"dyno= connect= service= status=503 bytes= protocol=https

But when I run it on the local server everything is clean

Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
August 30, 2020 - 19:01:48
Django version 3.0.3, using settings 'myfirst.settings'
Starting development server at 127.0.0.1:8000
Quit the server with CTRL-BREAK.
[30/Aug/2020 19:01:53] "GET / HTTP/1.1" 200 146

What is the problem

Procfile
web: gunicorn myfist.wsgi --log-file -
runtime.txt
python-3.7.9
.gitignore

__pycache__/
*pyc
db.sqlite3

requirements.txt

dj-database-url==0.5.0
Django==3.0.3
djangorestframework==3.11.0
gunicorn==20.0.4
oauthlib==3.1.0
PyJWT==1.7.1
requests==2.23.0
requests-oauthlib==1.3.0
six==1.14.0
whitenoise==5.2.0
wrapt==1.12.0
psycopg2==2.6.2