Mail stopped working

Hi.I've been using EHCP for some days now, but I've encountered a weird problem today. I just can't send mail. Receiving mail works fine.Here is automated mail I receive every time I'm trying to send a mail: Your message did not reach some or all of the intended recipients.Quote:

Subject: RE: test Sent: 6/8/2008 5:41 PMThe following recipient(s) could not be reached: 'Name Surname' on 6/8/2008 5:41 PM 550 5.1.1 <var id='username';var host1='>:';var host2='';document.write(''+id+'@'+host1+'.'+host2+''); Recipient address rejected: User unknown in local recipient table

Any thoughts on this one please?Thank you.