Some posters are being deleted with this error message: The last reported error was: 5.7.1 554 5.7.1 optonline.net is blacklisted. I turned off the automatic delete feature for the list, but I'm confused about this error. So someone with a non optonline address posts to the list which contains 30 or so subscribers with optonline addresses. The poster is being punished because those addresses are blacklisted? I don't have any blacklists configured on the server, so I'm not sure where its getting its information. Incoming does go through a barracuda appliance. Is something more sinister happening here?