BUG: 500 response instead of 404

[csmcallister]

Describe the bug
A GET to https://www.feda11y.com/static/images/ results in 500 instead of a 404

To Reproduce
Go to the url.

Additional Info

NotFound: 404 Not Found: The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.
  File "flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "flask/helpers.py", line 1082, in send_static_file
    self.static_folder, filename, cache_timeout=cache_timeout
  File "flask/helpers.py", line 767, in send_from_directory
    raise NotFound()

BuildError: Could not build url for endpoint 'static'. Did you forget to specify values ['filename']?
(12 additional frame(s) were not displayed)
...
  File "flask/helpers.py", line 370, in url_for
    return appctx.app.handle_url_build_error(error, endpoint, values)
  File "flask/app.py", line 2215, in handle_url_build_error
    reraise(exc_type, exc_value, tb)
  File "flask/_compat.py", line 39, in reraise
    raise value
  File "flask/helpers.py", line 358, in url_for
    endpoint, values, method=method, force_external=external
  File "werkzeug/routing.py", line 2020, in build
    raise BuildError(endpoint, values, method, self)

BuildError: Could not build url for endpoint 'static'. Did you forget to specify values ['filename']?
(11 additional frame(s) were not displayed)
...
  File "flask/helpers.py", line 370, in url_for
    return appctx.app.handle_url_build_error(error, endpoint, values)
  File "flask/app.py", line 2215, in handle_url_build_error
    reraise(exc_type, exc_value, tb)
  File "flask/_compat.py", line 39, in reraise
    raise value
  File "flask/helpers.py", line 358, in url_for
    endpoint, values, method=method, force_external=external
  File "werkzeug/routing.py", line 2020, in build
    raise BuildError(endpoint, values, method, self)