TEMPLATES = [{
  "BACKEND": "django.template.backends.django.DjangoTemplates",
  "DIRS": [],
  "APP_DIRS": True,   # <-- must be True
  "OPTIONS": {"context_processors": [
    "django.template.context_processors.request",
    "django.contrib.auth.context_processors.auth",
    "django.contrib.messages.context_processors.messages",
  ]},
}]

courses/templates/registration/login.html

path("accounts/login/",
     auth_views.LoginView.as_view(template_name="registration/login.html"),
     name="login")