I've had all messages sent over the listserve bounce from this user, and always get the following reason: ... while talking to vnet.ibm.com.: >>> MAIL From:<[log in to unmask]> <<< 501 Syntax Error. Unexpected Token '_' 554 <[log in to unmask]>,<[log in to unmask]>... Remote protocol error Can anyone tell me if it is because of the "_" in the user's address or in our node "AIIM_WEB.AIIM.ORG"? He receives all messages I send to him via the aiim.org node. From his end, the vnet.ibm.com gateway sends the message to an IBM VM then to a service machine called "delegate" then onto Notes. Any ideas? Thanks, Cheryl Chadwell AIIM [log in to unmask] ph: 301-587-8202 ext. 649 fx: 301-587-2711