Any emails being received by our qmail server are being delivered twice. This doesn't occur for outgoing emails. I've check the maillog and I don't see duplicates lines of the "starting delivery" messages, so I'm confused what is happening here. Any advice?? UPDATE: This is only affecting existing email addresses. If I delete an address and create it anew, the problem goes away. Could this be related to the latest Plesk upgrade? UPDATE: It looks like this is happening only for certain users. It also looks like this is happening due to 4PSA Spam Guardian, so I'm taking up the issue with them.