ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;
net4.0环境则加
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls | (SecurityProtocolType)0x300 //Tls11 | (SecurityProtocolType)0xC00; //Tls12标签:TLS,Tls,创建,ServicePointManager,SSL,Tls11,SecurityProtocolType From: https://www.cnblogs.com/jingjinggui/p/17387706.html