钉钉上传文件接口失败，-1 系统繁忙，求助

java测试代码如下：


public String uploadMedia2(String cropId, String url, File file)
            throws Exception {
        String mediaId = "";
        HttpPost httpPost = new HttpPost(url);
        Closeable HttpResponse response = null;
        Closeable HttpClient httpClient = HttpClients.createDefault();
        RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(2000).setConnectTimeout(2000).build();
        httpPost.setConfig(requestConfig);
        HttpEntity requestEntity = MultipartEntityBuilder
                .create()
                .addPart(
                        "media",
                        new FileBody(file,
                                ContentType.APPLICATION_OCTET_STREAM, file
                                        .getName())).build();
        httpPost.setEntity(requestEntity);
        try {
            response = httpClient.execute(httpPost, new BasicHttpContext());
            if (response.getStatusLine().getStatusCode() != 200) {
                return null;
            }
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                String resultStr = EntityUtils.toString(entity, "utf-8");
                JsonMapper jsonMapper = new JsonMapper();
                Map<String, String> result = jsonMapper.fromJson(resultStr,
                        Map.class);
                if (result.get("errcode") == "0") {
                    // 成功
                    result.remove("errcode");
                    result.remove("errmsg");
                    mediaId = result.get("media_id");
                    return mediaId;
                } else {
                    String errMsg = (String) result.get("errmsg");
                    throw new Exception(errMsg);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (response != null)
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
        return null;
    }