HttpClient请求时 WebException: 基础连接已经关闭: 连接被意外关闭(搞了一天，终于找到了办法)

	<system.net>
		<settings>
			<servicePointManager expect100Continue="false" />
			</settings>
	</system.net>

　　

 

 

  ServicePointManager.SecurityProtocol= SecurityProtocolType.Tls12;

from：https://blog.csdn.net/WhileG/article/details/128582444