[otrs] Problem with Auto Reply

Hi, I am having problem with sending auto reply, if someone[not existing customer] send email to OTRS ticketing system. I can see below message in log. Sent no 'auto reply' for Ticket [*****] (***********) because the sender doesn't want a auto-response (e. g. loop or precedence header) Could someone suggest me how to fix this issue? Thanks, Sridhar..