SMTP error when sending a email of domain with MX record pointing to another server.

I am using ISPconfig and have a problem when I send emails to a particular domain using my ISPconfig SMTP service

Due to some special reason, the domain simsen.com was hosted by an external DNS server, and the setting is:

MX record: point to another server : mail.simsen.com (202.82.25.9)
A record: point to www.simsen.com - my ISPconfig server (202.134.80.146)

I am using the ISPconfig SMTP service to send out email, it works fine for all other domains but when I send to [email protected], it will return the following error:

SMTP Error: Recipient not accepted. Verify your relay rules

When I view the mail log, it has the following error message:
Recipient address rejected: User unknown in local recipient table

I believe it is due to the fact that when I send email thru the ISPconfig server, it will first check the local recipient table, which has no record of [email protected], and so rejected the email sending request.

How can I fix this problem ? Thank you in advance.

 

Please select "External Mailserver" for that web site (on the "Options" tab) and also for the Co-Domains of that web site (each Co-Domain has its own "Options" tab where you can configure this).

 

Thanks a lot Falko.

I tried. The problem was fixed immediately

(I find that the domain simen.com is no longer in the local-host-names file now)