Question: After rebuild of my Django 4 Docker container the web service stopped working with this error:  zoneinfo._common.ZoneInfoNotFoundError: 'No time zone found with key Asia/Hanoi'  My setup is:  Python 3.10 Django 4.0.5  Error: web_1 Traceback (most recent call last): web_1 File "/usr/local/lib/python3.10/zoneinfo/_common.py", line 12, in load_tzdata web_1 return importlib.resources.open_binary(package_name, resource_name) web_1 File "/usr/local/lib/python3.10/importlib/resources.py", line 46, in open_binary web_1 return reader.open_resource(resource) web_1 File "/usr/local/lib/python3.10/importlib/abc.py", line 433, in open_resource web_1 return self.files().joinpath(resource).open('rb') web_1 File "/usr/local/lib/python3.10/pathlib.py", line 1119, in open web_1 return self._accessor.open(self, mode, buffering, encoding, errors, web_1 FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/lib/python3.10/site-packages/tzdata/zoneinfo/Asia/Hanoi' web_1 web_1 During handling of the above exception, another exception occurred: web_1 web_1 Traceback (most recent call last): web_1 File "/home/app/web/manage.py", line 22, in <module> web_1 main() web_1 File "/home/app/web/manage.py", line 18, in main web_1 execute_from_command_line(sys.argv) web_1 File "/usr/local/lib/python3.10/site-packages/django/core/management/__init__.py", line 446, in execute_from_command_line web_1 utility.execute() web_1 File "/usr/local/lib/python3.10/site-packages/django/core/management/__init__.py", line 420, in execute web_1 django.setup() web_1 File "/usr/local/lib/python3.10/site-packages/django/__init__.py", line 24, in setup web_1 apps.populate(settings.INSTALLED_APPS) web_1 File "/usr/local/lib/python3.10/site-packages/django/apps/registry.py", line 116, in populate web_1 app_config.import_models() web_1 File "/usr/local/lib/python3.10/site-packages/django/apps/config.py", line 304, in import_models web_1 self.models_module = import_module(models_module_name) web_1 File "/usr/local/lib/python3.10/importlib/__init__.py", line 126, in import_module web_1 return _bootstrap._gcd_import(name[level:], package, level) web_1 File "<frozen importlib._bootstrap>", line 1050, in _gcd_import web_1 File "<frozen importlib._bootstrap>", line 1027, in _find_and_load web_1 File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked web_1 File "<frozen importlib._bootstrap>", line 688, in _load_unlocked web_1 File "<frozen importlib._bootstrap_external>", line 883, in exec_module web_1 File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed web_1 File "/usr/local/lib/python3.10/site-packages/django_celery_beat/models.py", line 8, in <module> web_1 import timezone_field web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/__init__.py", line 1, in <module> web_1 from timezone_field.fields import TimeZoneField web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/fields.py", line 11, in <module> web_1 class TimeZoneField(models.Field): web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/fields.py", line 41, in TimeZoneField web_1 default_zoneinfo_tzs = [ZoneInfo(tz) for tz in pytz.common_timezones] web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/fields.py", line 41, in <listcomp> web_1 default_zoneinfo_tzs = [ZoneInfo(tz) for tz in pytz.common_timezones] web_1 File "/usr/local/lib/python3.10/zoneinfo/_common.py", line 24, in load_tzdata web_1 raise ZoneInfoNotFoundError(f"No time zone found with key {key}") web_1 zoneinfo._common.ZoneInfoNotFoundError: 'No time zone found with key Asia/Hanoi' web_1 [2022-08-12 09:18:36 +0000] [1] [INFO] Starting gunicorn 20.0.4 web_1 [2022-08-12 09:18:36 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1) web_1 [2022-08-12 09:18:36 +0000] [1] [INFO] Using worker: sync web_1 [2022-08-12 09:18:36 +0000] [11] [INFO] Booting worker with pid: 11 web_1 [2022-08-12 12:18:37 +0300] [11] [ERROR] Exception in worker process web_1 Traceback (most recent call last): web_1 File "/usr/local/lib/python3.10/zoneinfo/_common.py", line 12, in load_tzdata web_1 return importlib.resources.open_binary(package_name, resource_name) web_1 File "/usr/local/lib/python3.10/importlib/resources.py", line 46, in open_binary web_1 return reader.open_resource(resource) web_1 File "/usr/local/lib/python3.10/importlib/abc.py", line 433, in open_resource web_1 return self.files().joinpath(resource).open('rb') web_1 File "/usr/local/lib/python3.10/pathlib.py", line 1119, in open web_1 return self._accessor.open(self, mode, buffering, encoding, errors, web_1 FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/lib/python3.10/site-packages/tzdata/zoneinfo/Asia/Hanoi' web_1 web_1 During handling of the above exception, another exception occurred: web_1 web_1 Traceback (most recent call last): web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker web_1 worker.init_process() web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/workers/base.py", line 119, in init_process web_1 self.load_wsgi() web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi web_1 self.wsgi = self.app.wsgi() web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/app/base.py", line 67, in wsgi web_1 self.callable = self.load() web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/app/wsgiapp.py", line 49, in load web_1 return self.load_wsgiapp() web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp web_1 return util.import_app(self.app_uri) web_1 File "/usr/local/lib/python3.10/site-packages/gunicorn/util.py", line 358, in import_app web_1 mod = importlib.import_module(module) web_1 File "/usr/local/lib/python3.10/importlib/__init__.py", line 126, in import_module web_1 return _bootstrap._gcd_import(name[level:], package, level) web_1 File "<frozen importlib._bootstrap>", line 1050, in _gcd_import web_1 File "<frozen importlib._bootstrap>", line 1027, in _find_and_load web_1 File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked web_1 File "<frozen importlib._bootstrap>", line 688, in _load_unlocked web_1 File "<frozen importlib._bootstrap_external>", line 883, in exec_module web_1 File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed web_1 File "/home/app/web/config/wsgi.py", line 16, in <module> web_1 application = get_wsgi_application() web_1 File "/usr/local/lib/python3.10/site-packages/django/core/wsgi.py", line 12, in get_wsgi_application web_1 django.setup(set_prefix=False) web_1 File "/usr/local/lib/python3.10/site-packages/django/__init__.py", line 24, in setup web_1 apps.populate(settings.INSTALLED_APPS) web_1 File "/usr/local/lib/python3.10/site-packages/django/apps/registry.py", line 116, in populate web_1 app_config.import_models() web_1 File "/usr/local/lib/python3.10/site-packages/django/apps/config.py", line 304, in import_models web_1 self.models_module = import_module(models_module_name) web_1 File "/usr/local/lib/python3.10/importlib/__init__.py", line 126, in import_module web_1 return _bootstrap._gcd_import(name[level:], package, level) web_1 File "<frozen importlib._bootstrap>", line 1050, in _gcd_import web_1 File "<frozen importlib._bootstrap>", line 1027, in _find_and_load web_1 File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked web_1 File "<frozen importlib._bootstrap>", line 688, in _load_unlocked web_1 File "<frozen importlib._bootstrap_external>", line 883, in exec_module web_1 File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed web_1 File "/usr/local/lib/python3.10/site-packages/django_celery_beat/models.py", line 8, in <module> web_1 import timezone_field web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/__init__.py", line 1, in <module> web_1 from timezone_field.fields import TimeZoneField web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/fields.py", line 11, in <module> web_1 class TimeZoneField(models.Field): web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/fields.py", line 41, in TimeZoneField web_1 default_zoneinfo_tzs = [ZoneInfo(tz) for tz in pytz.common_timezones] web_1 File "/usr/local/lib/python3.10/site-packages/timezone_field/fields.py", line 41, in <listcomp> web_1 default_zoneinfo_tzs = [ZoneInfo(tz) for tz in pytz.common_timezones] web_1 File "/usr/local/lib/python3.10/zoneinfo/_common.py", line 24, in load_tzdata web_1 raise ZoneInfoNotFoundError(f"No time zone found with key {key}") web_1 zoneinfo._common.ZoneInfoNotFoundError: 'No time zone found with key Asia/Hanoi' web_1 [2022-08-12 12:18:37 +0300] [11] [INFO] Worker exiting (pid: 11) web_1 [2022-08-12 09:18:37 +0000] [1] [INFO] Shutting down: Master web_1 [2022-08-12 09:18:37 +0000] [1] [INFO] Reason: Worker failed to boot.  In the Django settings file: TIME_ZONE = 'UTC' USE_TZ = True  PS: As suggested in another post I added tzdata to my requirements file but nothing changed.

Answer: Downgrading the pytz version from 2022.2 to 2022.1 seems to have solved this issue for me.