Why is my django-crontab cronjob not working?

Question

I have a django-project with an app called app that has a file called cron.py with a function called my_job().

I want the my_job() function to be called every minute.

In my django-project/django-project/settings.py I have this:

INSTALLED_APPS = [
    'django_crontab',
    ...
]

...

CRONJOBS = [
    ('*/5 * * * *', 'app.cron.my_job')
]

My django-project/app/cron.py looks like this:

from .models import TestModel

def my_job():
    TestModel.objects.create(number=100)
    return True

Of course I ran : python3 manage.py crontab add And the terminal printed:

 adding cronjob: (62dd7536ac2c985925ee33743a070a4c) -> ('*/5 * * * *', 'app.cron.my_job')

To be safe I run: python3 manage.py crontab show And the terminal prints:

Project/ccc_nema -> ('*/5 * * * *', 'app.cron.my_job')

To check if evrything works I run: python3 manage.py crontab run someHash

Traceback (most recent call last):
  File "/home/anik/Workplace/Office Project/ccc_nema v2/core/manage.py", line 22, in <module>
    main()
  File "/home/anik/Workplace/Office Project/ccc_nema v2/core/manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django/core/management/__init__.py", line 446, in execute_from_command_line
    utility.execute()
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django/core/management/__init__.py", line 440, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django/core/management/base.py", line 402, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django/core/management/base.py", line 448, in execute
    output = self.handle(*args, **options)
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django_crontab/management/commands/crontab.py", line 29, in handle
    Crontab().run_job(options['jobhash'])
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django_crontab/crontab.py", line 126, in run_job
    job = self.__get_job_by_hash(job_hash)
  File "/home/anik/Workplace/Office Project/ccc_nema v2/env_python/lib/python3.10/site-packages/django_crontab/crontab.py", line 171, in __get_job_by_hash
    raise RuntimeError(
RuntimeError: No job with hash someHash found. It seems the crontab is out of sync with your settings.CRONJOBS. Run "python manage.py crontab add" again to resolve this issue!

The main issue: No matter how long I wait the job will not be executed automatically.

1. What am I doing wrong?