原因很可能是安全组未正确配置，需要添加对应的入站规则，允许HTTP请求或HTTPS请求。另外，也需要检查代码逻辑是否正确，是否正确指定了上传文件的路径。以下是示例代码：

import boto3
from botocore.exceptions import NoCredentialsError

def upload_to_aws(local_file, bucket, s3_file):
    s3 = boto3.client('s3')
  
    try:
        s3.upload_file(local_file, bucket, s3_file)
        print("Upload Successful")
        return True
    except FileNotFoundError:
        print("The file was not found")
        return False
    except NoCredentialsError:
        print("Credentials not available")
        return False

uploaded = upload_to_aws('path/to/local/file', 'bucket-name', 's3-file-name')

注意修改参数：local_file为本地文件路径，bucket为存储桶名称，s3_file为S3中的文件路径。