Network not reachable

[chilabot]

I'm getting this error:

$ goapp serve dispatch.yaml frontend/app.yaml backend/app.yaml
INFO     2015-10-12 17:29:08,926 devappserver2.py:763] Skipping SDK update check.
INFO     2015-10-12 17:29:08,992 api_server.py:205] Starting API server at: http://localhost:51422
INFO     2015-10-12 17:29:08,992 dispatcher.py:185] Starting dispatcher running at: http://localhost:8080
INFO     2015-10-12 17:29:08,995 dispatcher.py:197] Starting module "frontend" running at: http://localhost:8081
INFO     2015-10-12 17:29:09,001 dispatcher.py:197] Starting module "default" running at: http://localhost:8082
INFO     2015-10-12 17:29:09,001 admin_server.py:116] Starting admin server at: http://localhost:8000
WARNING  2015-10-12 17:29:43,558 dispatcher.py:762] Skipping dispatch.yaml rules because /_ah/api/explorer is not a dispatchable path.
INFO     2015-10-12 17:29:43,570 module.py:786] default: "GET /_ah/api/explorer HTTP/1.1" 302 -
socket.error 101
Traceback (most recent call last):
  File "/home/robert/applib/appEngine/go_appengine/lib/cherrypy/cherrypy/wsgiserver/wsgiserver2.py", line 1302, in communicate
    req.respond()
  File "/home/robert/applib/appEngine/go_appengine/lib/cherrypy/cherrypy/wsgiserver/wsgiserver2.py", line 831, in respond
    self.server.gateway(self).respond()
  File "/home/robert/applib/appEngine/go_appengine/lib/cherrypy/cherrypy/wsgiserver/wsgiserver2.py", line 2117, in respond
    for chunk in response:
  File "/home/robert/applib/appEngine/go_appengine/google/appengine/tools/devappserver2/endpoints/endpoints_server.py", line 121, in __call__
    yield self.dispatch(request, start_response)
  File "/home/robert/applib/appEngine/go_appengine/google/appengine/tools/devappserver2/endpoints/endpoints_server.py", line 138, in dispatch
    start_response)
  File "/home/robert/applib/appEngine/go_appengine/google/appengine/tools/devappserver2/endpoints/endpoints_server.py", line 172, in dispatch_non_api_requests
    return dispatch_function(request, start_response)
  File "/home/robert/applib/appEngine/go_appengine/google/appengine/tools/devappserver2/endpoints/endpoints_server.py", line 212, in handle_api_static_request
    response, body = discovery_api.get_static_file(request.relative_url)
  File "/home/robert/applib/appEngine/go_appengine/google/appengine/tools/devappserver2/endpoints/discovery_api_proxy.py", line 113, in get_static_file
    connection.request('GET', path, None, {})
  File "/usr/lib/python2.7/httplib.py", line 979, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib/python2.7/httplib.py", line 1013, in _send_request
    self.endheaders(body)
  File "/usr/lib/python2.7/httplib.py", line 975, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python2.7/httplib.py", line 835, in _send_output
    self.send(msg)
  File "/usr/lib/python2.7/httplib.py", line 797, in send
    self.connect()
  File "/usr/lib/python2.7/httplib.py", line 1178, in connect
    self.timeout, self.source_address)
  File "/usr/lib/python2.7/socket.py", line 571, in create_connection
    raise err
error: [Errno 101] Network is unreachable

I'm behind a proxy but:

$ echo $http_proxy 
http://localhost:31288/
$ echo $https_proxy 
http://localhost:31288/

Are correctly set. What could this be?

When connected directly to the internet it works.