==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.4.2
- Deployed with iRedMail Easy or the downloadable installer? Downloadable Installer
- Linux/BSD distribution name and version: CentOS Linux release 8.2.2004 (Core)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Remote Server returned '554 4.7.1 <host.ourdmain.com #4.7.1 smtp; 450 4.7.1 <name123.local.domain>: Helo command rejected: Host not found>'

Email comes from the purchasing system of our client.
When commented commented the line "reject_unknown_helo_hostname) the email pass through as expected but the problem is we are also receiving spam emails.
# HELO restriction
smtpd_helo_required = yes
smtpd_helo_restrictions =
    permit_mynetworks
    permit_sasl_authenticated
    check_helo_access pcre:/etc/postfix/helo_access.pcre
    reject_non_fqdn_helo_hostname
   #reject_unknown_helo_hostname

Is there a way to maintain a whitelist related to this settings?