Recently i faced issue to make http call to WebAPI which is supporting latest TLS12 or TLS11. But our client project framework uses .net 4.0 so it not support by default. To resolve this issue added below code (constructor of API or global level)
//Setting supported security protocol
//Setting supported security protocol
System.Net.ServicePointManager.SecurityProtocol
= SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls | (SecurityProtocolType)((SslProtocols)0x00000C00) | (SecurityProtocolType)((SslProtocols)0x00000300);
Here
(SecurityProtocolType)((SslProtocols)0x00000C00) is equivalent to Tls12
(SecurityProtocolType)((SslProtocols)0x00000300) is equivalent to Tls11
Ref: https://support.microsoft.com/en-us/help/3154520/support-for-tls-system-default-versions-included-in-the-net-framework
Ref: https://support.microsoft.com/en-us/help/3154520/support-for-tls-system-default-versions-included-in-the-net-framework
