Hello all, Running Exchange 5.5 SP I have a DL (I'll call it 'XYZ') that is made up of multiple DL's. For example, the recipients of DL 'XYZ' are DL's named '123', '456', '789'. In the past, when I sent to DL 'XYZ', the mail has been forward correctly. All of a sudden, now when I send to 'XYZ' i get a '554 Spam Relay detected' for DL '456'. However if I send directly to DL '456' the mail goes through fine. Why would Exchange think that DL '456' is spam relay when sending to DL 'XYZ'? Any help is appreciated