When trying to configure email routing for different accounts, not all domains as displayed.
Investigation has show that
Database: postfix »Table: domain"Postfix Admin - Virtual Domains"
isn't being updated to reflect all accounts.
This may be linked to
Database: postfix »Table: mailbox"Postfix Admin - Virtual Mailboxes"
whereby if no local email accounts have been setup, then mx_routing doesn't display options to set remote routing for a domain (account).