问调用购买负载均衡实例接口报错？

{"code":4000,"message":"\u8bf7\u6c42\u5931\u8d25\uff0c\u53c2\u6570[loadBalancerType]\u4e0d\u80fd\u4e3a\u7a7a\u3002","codeDesc":"InvalidParameter"}

https://lb.api.qcloud.com/v2/index.php?Action=CreateLoadBalancer&Forward=1&LoadBalancerType=2&Nonce=1966227363&Number=1&Region=gz&SecretId=AKIDeK6mjnUhSF5pRWr8JJVYQ8FGD3jFrTRU&Signature=k8sb71zX5rCt5kO8dbIadtVKLizNgjhkjV75j9FUwwc%3d&SignatureMethod=HmacSHA256&Timestamp=1539226831