REST API 批量操作报错500

我请求 http://192.168.28.118:9000/1.1/batch，
body参数是json格式为：

"requests": [
    {
        "method": "DELETE",
        "path": "http://192.168.28.118:9000/1.1/classes/committee/617fb8bcf51abd722b5944ce"
    },
    {
        "method": "DELETE",
        "path": "http://192.168.28.118:9000/1.1/classes/committee/617fb90ff51abd722b59453c"
    }
]

}

报错：POST http://192.168.28.118:9000/1.1/batch 500 (Internal Server Error)