Remote: Unhandled error about example HOT 1 OPEN

21:44:40  W2   info    Listen port 8001 in worker 2
21:44:40  W1   info    Listen port 8000 in worker 1
21:44:40  W3   info    Listen port 8002 in worker 3
21:44:40  W1   debug   Start example plugin
21:44:40  W1   debug   { set: { key: 'keyName', val: 100 } }
21:44:40  W1   debug   { get: 'keyName', return: 100 }
21:44:40  W1   debug   { res: 100, cache: undefined }
21:44:40  W1   debug   Connect to redis
21:44:40  W1   debug   Connect to pg
21:44:40  W1   warn    No redis service detected, so quit client
21:44:40  W2   error   TypeError [ERR_INVALID_URL]: Invalid URL: undefined
  onParseError (internal/url.js:259:9)
  new URL (internal/url.js:335:5)
  initAsClient (/node_modules/ws/lib/websocket.js:502:17)
  new WebSocket (/node_modules/ws/lib/websocket.js:71:7)
  new Metacom (/node_modules/metacom/lib/client.js:37:19)
  Object.<anonymous> (/application/domain/remote/start.js:8:19)
21:44:40  W2   info    Application started in worker 2
21:44:40  W4   error   TypeError [ERR_INVALID_URL]: Invalid URL: undefined
  onParseError (internal/url.js:259:9)
  new URL (internal/url.js:335:5)
  initAsClient (/node_modules/ws/lib/websocket.js:502:17)
  new WebSocket (/node_modules/ws/lib/websocket.js:71:7)
  new Metacom (/node_modules/metacom/lib/client.js:37:19)
  Object.<anonymous> (/application/domain/remote/start.js:8:19)
21:44:40  W1   debug   Connect to metacom
21:44:40  W4   info    Application started in worker 4
21:44:40  W3   error   TypeError [ERR_INVALID_URL]: Invalid URL: undefined
  onParseError (internal/url.js:259:9)
  new URL (internal/url.js:335:5)
  initAsClient (/node_modules/ws/lib/websocket.js:502:17)
  new WebSocket (/node_modules/ws/lib/websocket.js:71:7)
  new Metacom (/node_modules/metacom/lib/client.js:37:19)
  Object.<anonymous> (/application/domain/remote/start.js:8:19)
21:44:40  W1   error   TypeError [ERR_INVALID_URL]: Invalid URL: undefined
  onParseError (internal/url.js:259:9)
  new URL (internal/url.js:335:5)
  initAsClient (/node_modules/ws/lib/websocket.js:502:17)
  new WebSocket (/node_modules/ws/lib/websocket.js:71:7)
  new Metacom (/node_modules/metacom/lib/client.js:37:19)
  Object.<anonymous> (/application/domain/remote/start.js:8:19)
21:44:40  W1   info    Application started in worker 1
21:44:40  W3   info    Application started in worker 3
21:44:40  W5   error   TypeError [ERR_INVALID_URL]: Invalid URL: undefined
  onParseError (internal/url.js:259:9)
  new URL (internal/url.js:335:5)
  initAsClient (/node_modules/ws/lib/websocket.js:502:17)
  new WebSocket (/node_modules/ws/lib/websocket.js:71:7)
  new Metacom (/node_modules/metacom/lib/client.js:37:19)
  Object.<anonymous> (/application/domain/remote/start.js:8:19)
21:44:40  W5   info    Application started in worker 5