🚀 go-pugleaf

It's like this, i have a problem when I'm trying to send a mail. I can only
send mail to an adress that's on the mailserver i have writen in the source
code. If i try to send a mail to an adress that's not located at the
mailserver I get this error:

javax.servlet.ServletException: Sending failed;
  nested exception is:
 javax.mail.SendFailedException: Invalid Addresses;
  nested exception is:
 javax.mail.SendFailedException: 550 5.7.1 Unable to relay for
b2b01bo17@studentmail.ec.se

Howcome can't I send mail to whatever adress i want??

This is my sourcecode:

 Properties props = new Properties();
  props.put("mail.smtp.host", "themailserver.com");
  Session s = Session.getInstance(props,null);

  MimeMessage message = new MimeMessage(s);

  InternetAddress from = new InternetAddress(mrBean.getUser());
  message.setFrom(from);
  String toAddress = email;
  InternetAddress to = new InternetAddress(toAddress);
  message.addRecipient(Message.RecipientType.TO, to);
  String subject = help;
  message.setSubject(subject);

  String kundnr = request.getParameter("kundnr");
  String datum = request.getParameter("datum");
  String radio = request.getParameter("radio");
  String rubrik = request.getParameter("rubrik");
  String uppdrag = request.getParameter("uppdrag");

  message.setText("Kundnr: " +kundnr+"\nDatum: "+datum+"\nPrioritet:
"+radio+"\nRubrik: "+rubrik+"\nUppdrag: "+uppdrag);
  Transport.send(message);

Thanx in advance!