==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.8 MARIADB edition.
- Deployed with iRedMail Easy or the downloadable installer?
- Linux/BSD distribution name and version: Ubuntu 16.04.6 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): Mysql
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hi, how are you? I need help in releasing a domain to receive email. I have already done a brief survey and made some suggested adjustments and the problem still persists.

The log in the /var/log/mail.log file

Jun 16 02:03:56 srv-mx1 postfix/smtpd[25241]: NOQUEUE: reject: RCPT from infra-smtp-out-01.despegar.com[192.169.5.91]: 450 4.7.1 <infra-smtp-out-00.despegar.com>: Helo command rejected: Host not found; from=<atendimento@decolar.com> to=<gerencia1@iracemamarhotel.com.br> proto=ESMTP helo=<infra-smtp-out-00.despegar.com>

The cat in file /etc/postfix/helo_access.pcre

# Shipped within iRedMail project:
#   * http://www.iredmail.org/

# Liberação do E-mail Decolar
/^infra-smtp-out-01\.despegar\.com$/ OK
/^infra-smtp-out-00\.despegar\.com$/ OK

# Prepend HELO hostname of sender server
#/(.*)/ PREPEND X-Original-Helo: $1 (iRedMail: http://www.iredmail.org/)

I did the release through Regex and even then the email messages continue to be blocked. Is there another recommendation for this release?