==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.9
- Deployed with iRedMail Easy or the downloadable installer? Yes
- Linux/BSD distribution name and version:  Ubuntu 18.04 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Web server (Apache or Nginx):Apache
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hi ,

Can you please help us how we can enable and test the grey listing feature of the iredmail