==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version: iRedMail-1.6.8
- Upgraded with iRedAdmin-Pro-5.5
- Linux/BSD distribution name and version: Debian 12
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB/MySQL
- Web server (Apache or Nginx): NginX
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
I am experiencing two issues. I believe they are related. At least I hope so.

Adding an alias to a domain does not allow external email to be received. If I send from another account on the server, the email is received fine.  If I send an email from an account not on the server, it is bounced as user not found.  The first alias added on the domain works. The rest do not.  I have removed and added back, and the problem persists.

Similarly, for some domains, some of the email addresses cannot receive email from accounts not on the server. An email sent from an external account is bounced as user not found, but arrives fine when sent from an internal account.

This is a brand new install.  All accounts and aliases were added with the latest version of iRedAdmin-Pro using the Admin Panel.  A lot of accounts were removed as they had left.  All email was synced with the iMapSync program, so I know the accounts are working on the new server with the correct password as least as far as IMAP is concerned.  Some users are saying they cannor send with their accounts as well, but I have not had time to test much. Same root cause maybe?

Only the passwords were synced from the old server with the command:

UPDATE mailbox AS n INNER JOIN oldmailbox o on n.username = o.username SET n.password = o.password

Nothing to really post for the log. There is no record of the external email ever reaching the server.  I suppose it could be DNS related since the IP was changed, but that was 3 days ago and the TTL was set to 600.  I just changed the serial again, as I have nothing else to try.