RE: Error SMTP (450). Recipient address rejected: User unknown in virtual mailbox table
09-01-2018, 03:47 AM
(09-01-2018, 02:15 AM)Sonichaos Wrote: I saw this error before. It was present when you I configured one domain on Sentora panel but your MX records are pointing to an external mail service and try to send an email from one sentora server mail to the other domain configured to an external mail server. Then you receive this behavior. Maybe one of our experimented Sentora developers can help you.
Hi,
I am not one of the experienced Sentora developers but I have been looking into this and I believe the problem is something to do with this:
You have domain1.com and domain2.com configured on your server.
You use the webmail on your server to send an email from account@domain1.com to account@domain2.com. Now, even though you have MX records for domain2.com set to direct mail to an external third-party server, your own Sentora server (or more specifically Postfix, I think) resolves domain2.com locally to itself, because it sees that it is a domain you have configured on your server. In my testing, this DOES NOT happen if you have only added the domain and have NEVER added ANY mailboxes using that domain (domain2.com). The moment you add a mailbox using domain2.com, is the moment postfix starts looking for it locally. Even if you then subsequently delete the mailboxes, Postfix retains the domain info and keeps trying to resolve it locally.
This may all be incorrect, so forgive me if I am wrong, but is what I have found so far. Is it possible that you guys have added mailboxes for domain2.com in the past to your servers, OR are you sure you have ONLY ever added the domain for domain2.com and NEVER touched the mailbox/alias/forwarders etc. section?
Keith
