因为算法不同，客户端和服务器无法通信

.net 4.0 解决方式

ServicePointManager.SecurityProtocol = (SecurityProtocolType)768 | (SecurityProtocolType)3072;

.net 4.5解决方式

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12; 

 

以上代码可添加至通信调用之前，或进程启动初始化时