JavaScript API > Error: Operation is invalid for Message Consumer in disconnected

I am new to the Solace Javascript API and trying to read messages from a queue in the PubSub+ Broker Manager.

I kept running into the following error when calling solace.QueueBrowser.

Uncaught OperationError: Operation is invalid for Message Consumer in disconnected state

The funny thing is, when I run the script for a different Solace environment, I am unable to recreate this error (I.e. it connects correctly).

Below is the source code:

try {
    // Login to Solace
    var session = solace.SolclientFactory.createSession({
        url: loginDetails.url,
        vpnName: loginDetails.vpn,
        userName: loginDetails.username,
        password: loginDetails.pw
    });

    session.connect(); // Connect session
    var qb = session.createQueueBrowser({
        queueDescriptor: {
            name: dynamicQueueName,
            type: "QUEUE"
        }
    });
    qb.on(solace.QueueBrowserEventName.CONNECT_FAILED_ERROR,
        function connectFailedErrorEventCb(error) {
            console.error(error.message);
            sendErrorToPage(error.message);
        }); 
    qb.on(solace.QueueBrowserEventName.MESSAGE,
        function messageCB(message) {
            var appMsgId = message.getApplicationMessageId();
            if (appMsgId === undefined) { appMsgId = 'Not specified'; }
            var payload = message.getBinaryAttachment();
            sendPayloadToPage(message.rc.low, appMsgId, payload);        
        });
    // qb.connect(); // Connect with QueueBrowser to receive QueueBrowserEvents.
    setTimeout(
        function() {
            qb.disconnect();
            session.disconnect();
        }, 5000); // Disconnect after 5 seconds.
} catch (error) {
    console.error(error.message);
    sendErrorToPage(error.message);
}

Does anyone have ideas why this error is occurring? If so, what is going on and how do I correct it?