How to get rid of pytz UnknownTimeZoneError in my Django logs? – Apache

I’ve deployed a Django Application on Windows Server 2022 and error logs are flooded with the following message:

pytz.exceptions.UnknownTimeZoneError: 'Europe/Paris'r, referer: https://my_server_url
During handling of the above exception, another exception occurred

I’ve checked my pytz installation and it seems to work just fine :

# run Windows cmd as Apache service account
python manage.py shell
from django.conf import settings
import pytz
pytz.timezone(settings.TIME_ZONE)
<DstTzInfo 'Europe/Paris' LMT+0:09:00 STD>
settings.TIME_ZONE in pytz.all_timezones
True

I’ve tried to uninstall and reinstall my virtual environnement and upgrade/downgrade pytz, without success.

I’ve no idea on how to investigate this problem furthermore and how to solve it.

Here is the application setup :

Apache 2.4.52 (built from sources)
Python 3.10.4
Mod_wsgi 4.9.0
Django 3.2.9
pytz 2021.3

Edit 1.

Here are the relevant Django settings (I mostly use defaults):

TIME_ZONE = 'Europe/Paris'
USE_TZ = False
USE_L10N = False # also tried with True, same error

Edit 2.

Here is the full error traceback.

 # when any exception is raised in the app
 During handling of the above exception, another exception occurred:r, referer: https://my_server_url
 r, referer: https://my_server_url
 Traceback (most recent call last):r, referer: https://my_server_url
   File "path_to_venv\django\core\handlers\exception.py", line 47, in innerr, referer: https://my_server_url
     response = get_response(request)r, referer: https://my_server_url
   File "path_to_venv\django\utils\deprecation.py", line 117, in __call__r, referer: https://my_server_url
     response = response or self.get_response(request)r, referer: https://my_server_url
   File "path_to_venv\django\core\handlers\exception.py", line 49, in innerr, referer: https://my_server_url
     response = response_for_exception(request, exc)r, referer: https://my_server_url
   File "path_to_venv\django\core\handlers\exception.py", line 115, in response_for_exceptionr, referer: https://my_server_url
     log_response(r, referer: https://my_server_url
   File "path_to_venv\django\utils\log.py", line 224, in log_responser, referer: https://my_server_url
     getattr(logger, level)(r, referer: https://my_server_url
   File "C:\Program Files\Python3.10\Lib\logging\__init__.py", line 1497, in errorr, referer: https://my_server_url
     self._log(ERROR, msg, args, **kwargs)r, referer: https://my_server_url
   File "C:\Program Files\Python3.10\Lib\logging\__init__.py", line 1615, in _logr, referer: https://my_server_url
     self.handle(record)r, referer: https://my_server_url
   File "C:\Program Files\Python3.10\Lib\logging\__init__.py", line 1625, in handler, referer: https://my_server_url
     self.callHandlers(record)r, referer: https://my_server_url
   File "C:\Program Files\Python3.10\Lib\logging\__init__.py", line 1687, in callHandlersr, referer: https://my_server_url
     hdlr.handle(record)r, referer: https://my_server_url
   File "C:\Program Files\Python3.10\Lib\logging\__init__.py", line 967, in handler, referer: https://my_server_url
     self.emit(record)r, referer: https://my_server_url
   File "path_to_venv\django\utils\log.py", line 120, in emitr, referer: https://my_server_url
     message = "%s\n\n%s" % (self.format(no_exc_record), reporter.get_traceback_text())r, referer: https://my_server_url
   File "path_to_venv\django\views\debug.py", line 353, in get_traceback_textr, referer: https://my_server_url
     return t.render(c)r, referer: https://my_server_url
   File "path_to_venv\django\template\base.py", line 170, in renderr, referer: https://my_server_url
     return self._render(context)r, referer: https://my_server_url
   File "path_to_venv\django\template\base.py", line 162, in _renderr, referer: https://my_server_url
     return self.nodelist.render(context)r, referer: https://my_server_url
   File "path_to_venv\django\template\base.py", line 938, in renderr, referer: https://my_server_url
     bit = node.render_annotated(context)r, referer: https://my_server_url
   File "path_to_venv\django\template\base.py", line 905, in render_annotatedr, referer: https://my_server_url
     return self.render(context)r, referer: https://my_server_url
   File "path_to_venv\django\template\base.py", line 988, in renderr, referer: https://my_server_url
     output = self.filter_expression.resolve(context)r, referer: https://my_server_url
   File "path_to_venv\django\template\base.py", line 698, in resolver, referer: https://my_server_url
     new_obj = func(obj, *arg_vals)r, referer: https://my_server_url
   File "path_to_venv\django\template\defaultfilters.py", line 717, in dater, referer: https://my_server_url
     return formats.date_format(value, arg)r, referer: https://my_server_url
   File "path_to_venv\django\utils\formats.py", line 152, in date_formatr, referer: https://my_server_url
     return dateformat.format(value, get_format(format or 'DATE_FORMAT', use_l10n=use_l10n))r, referer: https://my_server_url
   File "path_to_venv\django\utils\dateformat.py", line 326, in formatr, referer: https://my_server_url
     df = DateFormat(value)r, referer: https://my_server_url
   File "path_to_venv\django\utils\dateformat.py", line 59, in __init__r, referer: https://my_server_url
     self.timezone = get_default_timezone()r, referer: https://my_server_url
   File "path_to_venv\django\utils\timezone.py", line 52, in get_default_timezoner, referer: https://my_server_url
     return pytz.timezone(settings.TIME_ZONE)r, referer: https://my_server_url
   File "path_to_venv\pytz\__init__.py", line 188, in timezoner, referer: https://my_server_url
     raise UnknownTimeZoneError(zone)r, referer: https://my_server_url