KeyError: u'\ufffd'

[Fclem]

View details in Rollbar: https://rollbar.com/fclem/Breeze/items/332/

Traceback (most recent call last):
  File "/homes/breeze/code/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 111, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "/homes/breeze/code/venv/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 77, in wrapped_view
    return view_func(*args, **kwargs)
  File "/homes/breeze/code/venv/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py", line 20, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "/homes/breeze/code/isbio/breeze/views.py", line 2256, in standalone_shiny_in_wrapper
    return aux.proxy_to(request, path + '/' + sub, settings.SHINY_LOCAL_STANDALONE_BREEZE_URL)
  File "/homes/breeze/code/isbio/breeze/auxiliary.py", line 518, in proxy_to
    data = data + each + "=" + urllib.quote_plus(request.POST[each]) + "&"
  File "/usr/lib/python2.7/urllib.py", line 1293, in quote_plus
    s = quote(s, safe + ' ')
  File "/usr/lib/python2.7/urllib.py", line 1288, in quote
    return ''.join(map(quoter, s))
KeyError: u'\ufffd'