Our overseas partners have a zimbra server set up. Now that a few of them are in the US they can access email through zimbra, but cannot email our domian. However, they can email yahoo and google email addresses. At this point I only have access to the web admin page, but adding out domain to the "domain" section did not help. They are receiving a relay error: 554 5.7.1 relay access denied when they try to email anyone using our exchange server. Any help would be appreciated.