We have been using ISPConfig to host for over a year. Without any problems. This past month we moved from a T1 circuit (Time Warner) to a fiber connection (Charter) on a different carrier - which meant new IP's for the servers. Everything has gone well except that some of our users are now getting the infamous: Recipient address rejected: User unknown in local recipient table Return email message. The odd part is that the emails being returned appear to be within Charter's domain for connectivity. I have poured over numerous forums and played with the Postfix main.cf to no avail. Any help in pointing me to the possible culprit would be greatly appreciated.
MX is good Falko, Thanks for the quick reply. I have been over the records and they are all good (hostnames and IP addresses). The particular account I can't email has their hosting with me (DNS and Web) but their email server is an in-house MS Exchange box.
Does this happen when emails are sent from your server or to your server? What's in the mail log when this happens?
