Here's the error:

```
Traceback (most recent call last):
  File "/var/apps/tango/envs/tango-env/local/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 187, in __call__
    self.load_middleware()
  File "/var/apps/tango/envs/tango-env/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 45, in load_middleware
    mw_class = import_by_path(middleware_path)
  File "/var/apps/tango/envs/tango-env/local/lib/python2.7/site-packages/django/utils/module_loading.py", line 21, in import_by_path
    module = import_module(module_path)
  File "/var/apps/tango/envs/tango-env/local/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
    __import__(name)
  File "/var/apps/tango/envs/tango-env/local/lib/python2.7/site-packages/django/middleware/doc.py", line 4, in <module>
    warnings.warn(__doc__, PendingDeprecationWarning, stacklevel=2)
TypeError: expected string or buffer

```

**TypeError: expected string or buffer**

Tango is the user I created specifically for this project.

I'm using upstart so in /etc/init/tango-wsgi.conf looks like:

```
exec /var/apps/tango/envs/tango-env/bin/uwsgi \
--uid tango \
--home /var/apps/tango/envs/tango-env \
--pythonpath /var/apps/tango/tango/src \
--wsgi-file /var/apps/tango/tango/src/tango_cms/wsgi.py \
--socket /tmp/tango-uwsgi.sock \
--chmod-socket \
--logdate \
--optimize 2 \
--processes 2 \
--master \
--logto /var/apps/tango/logs/uwsgi.log

```

**UPDATE:**

My nginx.conf has following entry:

```
location / {
        uwsgi_pass unix:/tmp/tango-uwsgi.sock;  
        include /etc/nginx/uwsgi_params;
}

```

Please help.