Django LookupError: No installed app with label 'admin'
Answering my own question, searching the net for informations regarding this error leads to many ambigous results, since this error seems to be fired even if the root cause was of another nature. In my case i forgot to apply the python manage.py makemigrations directive.
I'm trying to running the appserver with python manage.py runserver with python 3.8.2 and django 3.0.3. I've setup a mysql database connection and inserted my "myApp.apps.myAppConfig" into INSTALLED_APPS, declared a couple of database-view based models, a form and a view. Nothing that seems too out of the way for the tutorials i've found. When i run the python manage.py runserver command, this is the output:

Watching for file changes with StatReloader Performing system
  checks...
Exception in thread django-main-thread: Traceback (most recent call
  last):   File
  "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\apps\registry.py",
  line 155, in get_app_config
      return self.app_configs[app_label] KeyError: 'admin'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):   File
  "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\threading.py",
  line 932, in _bootstrap_inner
      self.run()   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\threading.py",
  line 870, in run
      self._target(*self._args, **self._kwargs)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\utils\autoreload.py",
  line 53, in wrapper
      fn(*args, **kwargs)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\commands\runserver.py",
  line 117, in inner_run
      self.check(display_num_errors=True)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\base.py",
  line 392, in check
      all_issues = self._run_checks(   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\base.py",
  line 382, in _run_checks
      return checks.run_checks(**kwargs)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\checks\registry.py",
  line 72, in run_checks
      new_errors = check(app_configs=app_configs)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\checks\urls.py",
  line 13, in check_url_config
      return check_resolver(resolver)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\checks\urls.py",
  line 23, in check_resolver
      return check_method()   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\urls\resolvers.py",
  line 407, in check
      for pattern in self.url_patterns:   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\utils\functional.py",
  line 48, in get
      res = instance.dict[self.name] = self.func(instance)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\urls\resolvers.py",
  line 588, in url_patterns
      patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)   File
  "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\utils\functional.py",
  line 48, in get
      res = instance.dict[self.name] = self.func(instance)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\urls\resolvers.py",
  line 581, in urlconf_module
      return import_module(self.urlconf_name)   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\importlib__init__.py",
  line 127, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)   File "", line 1014, in _gcd_import   File
  "", line 991, in _find_and_load   File
  "", line 975, in _find_and_load_unlocked 
  File "", line 671, in _load_unlocked
  File "", line 783, in
  exec_module   File "", line 219, in
  _call_with_frames_removed   File "C:\Users\celli\Desktop\Interventi Comuni\Python\django-projects\zabbixPyFace\zabbixPyFace\urls.py", line
  21, in 
      path('admin/', admin.site.urls),   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\utils\functional.py",
  line 224, in inner
      self._setup()   File "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\contrib\admin\sites.py",
  line 537, in _setup
      AdminSiteClass = import_string(apps.get_app_config('admin').default_site)   File
  "C:\Users\celli\AppData\Local\Programs\Python\Python38\lib\site-packages\django\apps\registry.py",
  line 162, in get_app_config
      raise LookupError(message) LookupError: No installed app with label 'admin'.

I tried searching big G for answers but there's many sources that can cause this problem, could any of you gurus provide some insight?
Update:
I've already checked the INSTALLED_APPS and django.contrib.admin is present: 
INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', # jupyter notebook plugin 'django_extensions', ]