Help mails are not getting deliverd in users mailbox

==== Required information ====
- iRedMail version: 0.9.0
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): IDK
- Web server (Apache or Nginx): Apache
- Linux/BSD distribution name and version: Centos 7 64 bit
- Related log if you're reporting an issue:
====

Hi,

If i use the command mailq i can see my mails in the query but somehow they are not getting deliverd in the users mailbox so i can't  see those mails? help me please.