SMTP Server (error message)

Hello again, I tried again sending a mail from a sendmail testpage and I received the following error message: Error number 4001 in 4: Error while parsing velocity page Demo.SendMailTestPage Wrapped Exception: Invocation of method 'sendMessage' in class com.xpn.xwiki.XWiki threw exception class com.xpn.xwiki.XWikiException : Error number 10003 in 10: Exception while sending email from to [Ljava.lang.String;@24797f Wrapped Exception: Connection refused Thanks for your help. I am pretty much lost. Jens