ValueError：无效端点：https://s3..amazonaws.com

Question

新手上路，请多包涵

当 EMR 机器尝试运行包含 boto3 初始化的步骤时，它有时会出现以下错误： ValueError: Invalid endpoint: https://s3..amazonaws.com 当我尝试设置一台新机器时，它可能突然工作。附上完整错误：

 self.client = boto3.client("s3")
  File "/usr/local/lib/python3.6/site-packages/boto3/__init__.py", line 83, in client
    return _get_default_session().client(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/boto3/session.py", line 263, in client
    aws_session_token=aws_session_token, config=config)
  File "/usr/local/lib/python3.6/site-packages/botocore/session.py", line 861, in create_client
    client_config=config, api_version=api_version)
  File "/usr/local/lib/python3.6/site-packages/botocore/client.py", line 76, in create_client
    verify, credentials, scoped_config, client_config, endpoint_bridge)
  File "/usr/local/lib/python3.6/site-packages/botocore/client.py", line 285, in _get_client_args
    verify, credentials, scoped_config, client_config, endpoint_bridge)
  File "/usr/local/lib/python3.6/site-packages/botocore/args.py", line 79, in get_client_args
    timeout=(new_config.connect_timeout, new_config.read_timeout))
  File "/usr/local/lib/python3.6/site-packages/botocore/endpoint.py", line 297, in create_endpoint
    raise ValueError("Invalid endpoint: %s" % endpoint_url)
ValueError: Invalid endpoint: https://s3..amazonaws.com

知道为什么会这样吗？

（版本：boto3==1.7.29，botocore==1.10.29）