==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): latest release pro version
- Deployed with iRedMail Easy or the downloadable installer? downloadable installer
- Linux/BSD distribution name and version:  : Debian Linux 9
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): 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.
====

hi,

one of our customers' account is receving the following message even after around 5 days after sending a message to the mailing list

mailing list name : common@customerdomain.com

#######################
Hi, this is the Mlmmj program managing the common@customerdomain.com mailing list.

Some messages to you could not be delivered. If you're seeing this message it means things are back to normal, and it's merely for your information.

Here is the list of the bounced messages:
- 1
#######################

what could be reason for this and how to stop the same.

thanks
rajesh