==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.0
- Deployed with iRedMail Easy or the downloadable installer? downloadable
- Linux/BSD distribution name and version: Ubuntu 18.04LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- 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.
====

I installed an iRedmail instance without Webmail. This instance is used to parse incoming emails and saves the results into DB. However, some users recently complained about some emails they are sure sent missing. They found this out by requesting a copy to their own mailboxes, and they found these emails landed in their own mailboxes, but not in our data.

How should I go about checking if those emails are actually saved by my iRedmail instance and are sitting somewhere on the server, or they are filtered by iRedmail?

Thanks!