Original setup as follows: Web and MX record pointed to: 18.104.22.168 for stingray-webdesign.com All email addresses work fine there. Then: Installed a new instance of ispconfig at 22.214.171.124. Pointed Web and MX record to 126.96.36.199. Now all my emails get bounced back to me stating: The following recipient(s) could not be reached: [email protected] on 2/5/2007 3:49 PM The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address. <smail.lasalletown.com #5.1.1 smtp;550 5.1.1 <[email protected] I have other domains running at 188.8.131.52 and I have no problems with the emails with them, only with this domain. This specific domain is the host of the ISPConfig server (webserver.stingray-webdesign.com). For example you can email [email protected] and have a successful send, but when you email [email protected] your email will be bounced back.