Hi, I am using horde 2.1 and IMP 3.1 on Redhat 7.3 and using sendmail as mailing agent. Everything is fine but when sending mail after composing mail and click send button, it will display "page not found" error, please anyone guide me for any configuration for sendmail in horde or IMP, so that i will be able to send mail's Thanks in advance, Kiran system administrator.