invalid token in plural form: EXPRESSION

url http://127.0.0.1:8000/ms/

Environment:

Request Method: GET
Request URL: http://127.0.0.1:8000/ms/

Django Version: 2.2.8
Python Version: 3.6.9
Installed Applications:
['apps.admin_shortcuts',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.admin',
'django.contrib.sites',
'django.contrib.sitemaps',
'django.contrib.staticfiles',
'django.contrib.messages',
'django.contrib.humanize',
'rest_framework',
'ckeditor',
'cms',
'menus',
'sekizai',
'treebeard',
'djangocms_text_ckeditor',
'filer',
'easy_thumbnails',
'djangocms_file',
'djangocms_link',
'djangocms_picture',
'djangocms_style',
'djangocms_snippet',
'djangocms_googlemap',
'djangocms_video',
'fourgg',
'mptt',
'apps.cmsplugins_bootstrap4',
'apps.visitor',
'apps.member',
'apps.vendor',
'apps.accounting',
'apps.affiliate']
Installed Middleware:
['cms.middleware.utils.ApphookReloadMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.locale.LocaleMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'django.contrib.sites.middleware.CurrentSiteMiddleware',
'cms.middleware.user.CurrentUserMiddleware',
'cms.middleware.page.CurrentPageMiddleware',
'cms.middleware.toolbar.ToolbarMiddleware',
'cms.middleware.language.LanguageCookieMiddleware',
'apps.affiliate.middleware.RememberAgentMiddleware']

Traceback:

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner
34. response = get_response(request)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/deprecation.py" in call
93. response = self.process_request(request)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/middleware/locale.py" in process_request
25. translation.activate(language)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/translation/init.py" in activate
170. return _trans.activate(language)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/translation/trans_real.py" in activate
208. _active.value = translation(language)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/translation/trans_real.py" in translation
197. _translations[language] = DjangoTranslation(language)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/translation/trans_real.py" in init
96. self._add_installed_apps_translations()

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/translation/trans_real.py" in _add_installed_apps_translations
144. translation = self._new_gnu_trans(localedir)

File "/home/program1/fourgg/venv/lib/python3.6/site-packages/django/utils/translation/trans_real.py" in _new_gnu_trans
122. fallback=use_null_fallback,

File "/usr/lib/python3.6/gettext.py" in translation
538. t = translations.setdefault(key, class(fp))

File "/usr/lib/python3.6/gettext.py" in init
254. self._parse(fp)

File "/usr/lib/python3.6/gettext.py" in _parse
394. self.plural = c2py(plural)

File "/usr/lib/python3.6/gettext.py" in c2py
177. result, nexttok = _parse(_tokenize(plural))

File "/usr/lib/python3.6/gettext.py" in _parse
114. nexttok = next(tokens)

File "/usr/lib/python3.6/gettext.py" in _tokenize
91. raise ValueError('invalid token in plural form: %s' % value)

Exception Type: ValueError at /ms/
Exception Value: invalid token in plural form: EXPRESSION

Start with the reported GET request and traceback, then inspect django/utils/translation/trans_real.py and the Python gettext.py plural-expression parser, especially c2py and _tokenize. Reproduce the invalid plural-form failure and identify the affected translation input; done means the issue has a confirmed cause and a regression check or clearly documented resolution.