[aposi]

Hola,
tal vez necesitat una conexio segura
revisa este codigo:

Código Delphi [-]
procedure TForm2.enviarmail;
var
  SMTP: TIdSMTP;
  Email: TIdMessage;
  SSLHandler: TIdSSLIOHandlerSocketOpenSSL;
  
begin
 

  SMTP := TIdSMTP.Create(nil);
  Email := TIdMessage.Create(nil);
  SSLHandler := TIdSSLIOHandlerSocketOpenSSL.Create(nil);

  try
    SSLHandler.MaxLineAction := maException;
    SSLHandler.SSLOptions.Method := sslvTLSv1;
    SSLHandler.SSLOptions.Mode := sslmUnassigned;
    SSLHandler.SSLOptions.VerifyMode := [];
    SSLHandler.SSLOptions.VerifyDepth := 0;
    SMTP.IOHandler := SSLHandler;
    SMTP.Host := 'smtp.gmail.com';
    SMTP.Port := 587;
    SMTP.Username := 'USUARIO';
    SMTP.Password := '********';
    SMTP.UseTLS := utUseExplicitTLS;
    Email.From.Address := 'REMITENTE';
    Email.Recipients.EmailAddresses := A QUIEN ENVIAS';
    Email.Subject := 'ASUNTO';
    Email.Body.Add('texto del correo');
    SMTP.Connect;
    SMTP.Send(Email);
    SMTP.Disconnect;

  finally
    SMTP.Free;
    Email.Free;
    SSLHandler.Free;
  end;
end;

Necesitaras las librerias de openssl
https://www.openssl.org/related/binaries.html