System mail accounts returning 550 No such recipient here

Recently migrated from CentOS 7 to CentOS 8.

The system user mailboxes were imported, and I can log into them (Roundcoube reports them as <systemaccountname>@localhost). Directadmin reads the accounts current status just fine, but Exim reports the boxes as "550 No such recipient here" when attempting to send new mail to them.

Reject log just simply shows "rejected RCPT", normal log shows the same.

I have compiled exim and rewritten exim configs via custombuild to no avail. All non-system accounts work correctly as does SNI. I'm not sure if this is CentOS 8 specific or not yet.
Any insight or suggestions would be appreciated.

Edit: outgoing from these accounts via SMTP also gives a "verification failed" message. Roundcube will send, but I'm pretty sure that is bypassing SMTP.

Bump. Still haven't found a solution for this.

This has been resolved. The hostname was erroneously added (by me) as a domain in attempt to generate SSL certificates, but it resulted in hostname confusion, so local accounts were rejected because they didn't exist under the server host domain.

Solution is to remove the domain that matches the hostname, and make sure it exists in /etc/virtual/domains but NOT in /etc/virtual/domainowners

Just posting in case anyone else runs into such an issue.

I'm having this same problem, but with one of the two domains I created an SSL cert for. Can you please elaborate on your solution? I have added the domain name as host name for this SSL cert and now my Exim says rejected RCPT [email protected]: in the logfile and 550 No such recipient here when I telnet to port 25 and try the users' address as rcpt to:..

Make sure your server has a unique subdomain as a hostname (IE server.example.com) and not a primary domain (IE example.com), and make sure that unique hostname does not exist as a subdomain or primary domain on any accounts (A/CNAME record is okay).

Then manually verify your /etc/virtual/domains and /etc/virtual/domainowners are correct.
/etc/virtual/domains should include your unique hostname
/etc/virtual/domainowners should not include your unique hostname