[otrs] [Fwd: automated response on 2.23]

Hi, I have a problem with automated responses. If an email is sent into the system by an email address that has never sent to the system, the auto response fails with Can't send to: XXXX@XXX.com! Enable debug for more info! if the user sends any other email to open a new ticket after the first one everything works fine. I have tried to enable the debug in SMTP.pm and I guess the debug is in the apache error.log but cannot find any debug information popping up in the log in relation to SMTP. Can anyone tell me A) where is the debug log stored, and B)if this problem is a known one with a known fix. Cheers, Dean.