You can set this somewhere to use TLS 1.2 with SmtpClient (works for me):
System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;
You can set this somewhere to use TLS 1.2 with SmtpClient (works for me):
System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;
Be mindful of the dark side...