When sending SMTP EMAIL getting error - SSL not available on the server error | Delphi | Indy

Error

When sending SMTP EMAIL getting error - SSL not available on the server error | Delphi | Indy

Cause

When IdSSLIOHandlerSocket’s SSL versions property is not assigned then SSLVersion will be set to TLSV1 by default, but server may expect latest versions due to that this issue may come.

Solution

Use IdSSLIOHandlerSocket’s SSLOptions.SSLVersions property instead of its SSLOptions.Method property,and then set SSLVersions to [sslvTLSv1, sslvTLSv1_1, sslvTLSv1_2]

IdSSLIOHandlerSocket1.SSLOptions.SSLVersions := [sslvTLSv1, sslvTLSv1_1, sslvTLSv1_2];

so the client can negotiate use of TLS 1.0, 1.1, or 1.2 depending on which one the server allows.