django.contrib.messages.middleware.MessageMiddleware错误

这是工作之前，但现在它给我一个错误。我使用内置消息显示错误、信息或成功消息。当数据导入失败时，系统必须执行message.error，但它会创建一个错误

例外情况：

Types:  MessageFailure

Value:  You cannot add messages without installing django.contrib.messages.middleware.MessageMiddleware

当我在设置中间件中跟踪代码时，消息就在那里

MIDDLEWARE_CLASSES = [
    'django.middleware.gzip.GZipMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    # Uncomment the next line for simple clickjacking protection:
    # 'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

TEMPLATE_CONTEXT_PROCESSORS = (
    "django.contrib.auth.context_processors.auth",
    "django.core.context_processors.debug",
    "django.core.context_processors.i18n",
    "django.core.context_processors.media",
    "django.core.context_processors.static",
    "django.core.context_processors.tz",
    "django.contrib.messages.context_processors.messages",
    "django.core.context_processors.request",
)

INSTALLED_APPS = [
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.humanize',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.markup',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'django.contrib.admin',
    'django.contrib.admindocs',
]

以下是捕获错误的代码：

try:
    .......
except Exception, e:
    code = '000'
    if hasattr(e, 'code'):
        code = e.code
    msg = 'No message returned from the server'
    if hasattr(e, 'msg'):
        msg = e.msg
    messages.error(
        request,
            'Error connecting to OFX server. URL: {0} ERROR: '
            '{1} {2}'.format(self.account.bank.ofx_url, code, msg))
    return ''
return req.text

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模板\u上下文\u处理器包含'django.contrib.messages.CONTEXT\u处理器.messages'？