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Enable SNI (Server Name Indication) extension
Server Name Indication extension is required by some servers (including Google AppEngine and Google services) to provide the correct X.509 certificate for the TLS handshake.
The extension is enabled in the following way (C# code):
SSLClient.Extensions.ServerName.Enabled = true;
SSLClient.Extensions.ServerName.NameType = TSBSSLServerNameType.ntHostName;
// the host name of the web server you are connecting to
SSLClient.Extensions.ServerName.Name = "mail.google.com";
Starting from SecureBlackbox 12 this extension is automatically enabled for TLS 1.1 and TLS 1.2 in all TElSSLClient-based components, but it can be disabled via Options or SSLOptions property where available.