Getting the error : Exception reading response; Unrecognized SSL message, plaintext connection?

UserName = '[e-mail]';

passWord = 'xxxxxx';

setpref('Internet','E_mail',UserName);

setpref('Internet','SMTP_Server','smtp.gmail.com');

setpref('Internet','SMTP_Username',UserName);

setpref('Internet','SMTP_Password',passWord);

props = java.lang.System.getProperties;

props.setProperty('mail.smtp.auth','true');

props.setProperty('mail.smtp.socketFactory.class', 'javax.net.ssl.SSLSocketFactory') ;

props.setProperty('mail.smtp.socketFactory.port','587');

emailto = '[e-mail]'; % recipient's email

sendmail(emailto, 'My Subject', 'My message');

Getting the error : Exception reading response;

Unrecognized SSL message, plaintext connection?

I know someone got the same problem (and it was almost the same topic), but I didn't find my solution on his topic ....