Conflict error using twilio conversations react?

I'm using Twilio conversations, First participant and second participant are OK

channelName is OK

Token is OK

The conversation of the user is shown on (the app with no problem) but on web I'm getting error below

Code >

    const onConversationJoined = (conversation) => {
      conversation.add(secondPerson.id).then(() => setConversation(conversation));
    };

    const onConversationFound = (conversation) => {
      if (conversation.status !== "joined") {
        conversation.join().then(onConversationJoined);
      } else {
        setConversation(conversation);
      }
      conversation.on("messageAdded", handleNewMessage);
      onConnected();
    };

    const onConversationNotFound = (client) => {
      client
        .createConversation({
          uniqueName: channelName,
        })
        .then(onConversationFound)
        .catch((e) => console.log(e, "error"));   << ERROR APPEAR HERE
    };

    if (token) {
      const client = new Client(token);
      client.on("stateChanged", (state) => {
        if (state === "initialized") {
          client
            .getConversationByUniqueName(channelName)
            // following line dont run..
            .then(onConversationFound)
            .catch(() => onConversationNotFound(client));
        }
      });
    }

Error > with code https://www.twilio.com/docs/api/errors/50353

The error shown on console.log

Error: Conflict
    at Upstream._callee$ (upstream.ts:179:1)
    at tryCatch (regeneratorRuntime.js:86:1)
    at Generator._invoke (regeneratorRuntime.js:66:1)
    at Generator.next (regeneratorRuntime.js:117:1)
    at asyncGeneratorStep (asyncToGenerator.js:3:1)
    at _next (asyncToGenerator.js:25:1) 'error'

Thanks!