[otrs] Sent no 'auto reply' for Ticket

Hello, I set up otrs on debian wheezy and it was working fine. After sometime auto response mails stop working. When I check the system logs it gives the log Sent no 'auto reply' for Ticket I searched for this a lot, And found that x-loop header should not be mention in mail filter for queue. I don't have x-loop header in mail filter queue. I also found that this is not a error of otrs your mailing list is blocking of mail filter queue with x-loop header. I don't have any x-loop header in mail filter queue. If this is not the problem in otrs then how it was working before and stop working after sometime. I am able to sent email notification manually editing responses. Regards Amit Bondwal