问ios 上传图片失败 403？

QCloudServiceConfiguration* configuration = [QCloudServiceConfiguration new];

    configuration.appID = @"xxx";

    configuration.signatureProvider = self;

    QCloudCOSXMLEndPoint* endpoint = [[QCloudCOSXMLEndPoint alloc] init];

    endpoint.regionName = @"ap-guangzhou";//服务地域名称，可用的地域请参考注释

    configuration.endpoint = endpoint;

    [QCloudCOSXMLService registerDefaultCOSXMLWithConfiguration:configuration];

    [QCloudCOSTransferMangerService registerDefaultCOSTransferMangerWithConfiguration:configuration];

实现代理  获取签名信息

/*向签名服务器请求临时的 Secret ID,Secret Key,Token*/

                QCloudCredential* credential = [QCloudCredential new];

                credential.secretID = credentDict[@"tmpSecretId"];

                credential.secretKey = credentDict[@"tmpSecretKey"];

                credential.token = credentDict[@"sessionToken"];

                credential.experationDate     = [NSDate dateWithTimeIntervalSince1970:[dataDict[@"expiredTime"] doubleValue]];/*签名过期时间*/

                QCloudAuthentationV5Creator* creator = [[QCloudAuthentationV5Creator alloc] initWithCredential:credential];

                QCloudSignature* signature =  [creator signatureForData:urlRequst];

                continueBlock(signature, nil);

上传图片

QCloudCOSXMLUploadObjectRequest* put = [QCloudCOSXMLUploadObjectRequest new];

    NSURL* url = [NSURL  fileURLWithPath:strPath];

    put.object = strImageName;

    put.bucket = @"xxx-xxxxx";

    put.body =  url;

    [put setSendProcessBlock:^(int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend) {

        NSLog(@"腾讯云upload %lld totalSend %lld aim %lld", bytesSent, totalBytesSent, totalBytesExpectedToSend);

    }];

    [put setFinishBlock:^(id outputObject, NSError* error) {

        NSLog(@"腾讯云上传结果%@    %@",outputObject,error);

    }];

    [[QCloudCOSTransferMangerService defaultCOSTransferManager] UploadObject:put];

结果报错 腾讯云上传结果(null)    Error Domain=com.tencent.qcloud.networking Code=403 "" UserInfo={NSLocalizedDescription=}