Describe the bug

I implemented the Direct Line App Service Extension(Node.js version) according to the official website suggestion, but I encountered some problems during the implementation. (https://github.com/microsoft/BotFramework-WebChat/tree/master/samples/01.getting-started/i.protocol-direct-line-app-service-extension)

I successfully got the token, but encountered a websocket error when establishing a connection

Error message from Chrome[F12]:
webchat-minimal.js:2 WebSocket connection to 'wss://chatbot-nodejs-bot-channel.azurewebsites.net/.bot/v3/directline/conversations/connect?token=undefined' failed: Error during WebSocket handshake: Unexpected response code: 500

[Bug]