Error: WebSocket is not open: readyState 2 (CLOSING)

[nightmarefsm007]

Ulixee Cloud listening at localhost:1818
2025-08-28T20:22:48.709Z ERROR [hero-core\index] UnhandledRejection { context: {}, sessionId: null, sessionName: undefined } Error: WebSocket is not open: readyState 2 (CLOSING)

[blakebyrnes]

This is not enough to go off of for a ticket. Can you include more details about your setup and scenario where this is occurring?

[entrptaher]

tsx ./hero.ts                          SIGINT(2) ↵  10073  01:08:58 
CloudNode started at: localhost:3001
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36
Rendering Engine: 139.0.7258.155
(node:9035) [DEP0194] DeprecationWarning: Priority signaling has been deprecated as of RFC 9113.
(Use `node --trace-deprecation ...` to show where the warning was created)
2025-12-27T19:10:01.941Z ERROR [hero-core/index] UnhandledRejection { context: {}, sessionId: null, sessionName: undefined } Error: WebSocket is not open: readyState 2 (CLOSING)
    at sendAfterClose (.../node_modules/.pnpm/ws@8.18.3/node_modules/ws/lib/websocket.js:1134:17)
    at WebSocket.send (.../node_modules/.pnpm/ws@8.18.3/node_modules/ws/lib/websocket.js:461:7)
    at .../node_modules/.pnpm/@ulixee+net@2.0.0-alpha.34/node_modules/net/lib/WsUtils.ts:14:8
    at new Promise (<anonymous>)
    at wsSend (.../node_modules/.pnpm/@ulixee+net@2.0.0-alpha.34/node_modules/net/lib/WsUtils.ts:13:9)
    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)
    at async WsTransportToClient.send (.../node_modules/.pnpm/@ulixee+net@2.0.0-alpha.34/node_modules/net/lib/WsTransportToClient.ts:40:7)
    at async ConnectionToHeroClient.handleRequest (.../node_modules/.pnpm/@ulixee+hero-core@2.0.0-alpha.34/node_modules/core/connections/ConnectionToHeroClient.ts:104:7)

Very random error.

[rommmy]

Ran into the same issue, and the fix for me was to change the way the connection object is passed on the Hero side.

Instead of doing this:

return new Hero({
  ...
  connectionToCore: {
    host: HERO_CORE_HOST,
  },
});

Doing this suppresses the socket closing error on the cloud side:

import Hero, { ConnectionToHeroCore } from "@ulixee/hero";

return new Hero({
  connectionToCore: ConnectionToHeroCore.remote(HERO_CORE_HOST),
});