We have a SharePoint site (MOSS 2007) that is enabled to send email to lists. It has been working fine, but now when we mail enable a new list the email is being rejected by the MOSS server:"Delivery has failed to these recipients or distribution lists:landscape@xyz.comYour message wasn't delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.The following organization rejected your message: moss-01.xyz.com.""moss-01.corp.xyz.com #550 5.7.1 Unable to relay for it@design.xyz.com "moss-01.corp.xyz.com is our MOSS server and design.xyz.com is the SharePoint site name.The email enabled lists that were previously created still work fine.We are on Exchange 2007. The only recent network changes was the replacement of a DC. There are no event log entries that appear to be related. I posted this earlier in the SharePoint forum and have had no replies, so thought I would try here since it is Exchange related.ThanksDon't sweat the hard stuff."

I figured it out. I setup an alias domain on the Moss server smtp service that matched the SharePoint site name. I still don't understand why it was still working for lists that were already mail enabled.Don't sweat the hard stuff."