I have followed every video and text on installing SMTP email on a localhost copy of DotNetNuke so I can test email alerts through gmail using DotNetNuke.Services.Mail.Mail.SendEmail() code.  I am running Win XP, IIS 5.1, DNN 5.06.

SMTP setting on Host are:

[L]SMTP Server and port: [L]Enter the SMTP Server Address. You can also specify an alternate port by adding a colon and the port number (e.g. smtp.googlemail.com:587). Enter the SMTP server name only to use default port number (25)	[L]Test [L]There has been an error trying to send the test email. The error is: [L]There is a problem with the configuration of your SMTP Server. Mail was not sent.
[L]SMTP Authentication: [L]Enter the SMTP Server Authentication method ( default = Anonymous )	[L]Anonymous [L]Basic [L]NTLM
[L]SMTP Enable SSL: [L]Used for SMTP services that require secure connection (usually not needed)
[L]SMTP Username: [L]Enter the Username for the SMTP Server	mygmailusernamehere
[L]SMTP Password: [L]Enter the Password for the SMTP Server	mygmailuserpasswordhere

Error Message on Test in code is:
[L]Error: QHWeb PaymentUpdates is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: Server does not support secure connections. ---> System.Net.Mail.SmtpException: Server does not support secure connections. at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port) at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port) at System.Net.Mail.SmtpClient.GetConnection() at System.Net.Mail.SmtpClient.Send(MailMessage message) at DotNetNuke.Services.Mail.Mail.SendEmail(String fromAddress, String senderAddress, String toAddress, String subject, String body) at DotNetNuke.Services.Mail.Mail.SendEmail(String fromAddress, String toAddress, String subject, String body) at QHWeb.Modules.PaymentUpdates.View.cmdTestEmail_Click(Object sender, EventArgs e) in C:\Inetpub\wwwroot\DotNetNuke\DesktopModules\QHWeb\PaymentUpdates\View.ascx.cs:line 573 --- End of inner exception stack trace ---