==== Required information ====
- iRedMail version (check /etc/iredmail-release):
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- Related log if you're reporting an issue:
====

CentOS MySQL iRedAdmin-Pro

Email from a third party vendor using a Java Application for lead systems is sending email to our system user as the user. 
Example:  some_user@domain_name.tld is hosted on the iRedAdmin-Pro system.  Have a vendor that makes sends e-mail from their JavaMail system as some_user@domain_name.tld.

I believe this is blocked as spam since known not to the host.  However, not sure where this value is adjusted in the new release and changes. 

Can you advise of where to adjust this so that such email will pass? 
Can you advise of where to adjust if want "system" wide e-mail to be accepted when known sender is local?

Not that I want to open entire system but was curious about settings (if in iRedAPD)...

Thanks