Hello,
When I email a local account’s email from another local account, and where the recipient has an external mx-record, I get “user unknown” as an error reply.
How do I get rid of this? (Is there a “clean up command” to use for the email settings on a specific domain?)
There are no local aliases or mailboxes now added for the recipient domain that gives these user unknown errors.
A fast response would be appreciated! 
TIA