==== Required information ====
- iRedMail version: Latest
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx):  Apache
- Linux/BSD distribution name and version:  CentOS 7
- Related log if you're reporting an issue: (NOQUEUE: reject: RCPT...) and (Greylisting in effect, please come back later)
====

Good evening.  I have Pro, but I'm not sure if I can fix this through it.  I suspect there's a SPAM/greylisting check going on, but there are many instances where my clients are not receiving emails for up to two hours.  My logs give the message "Greylisting in effect, please come back later" so is there a way to make this more efficient?  If not, is there a way to turn it off?

thanks for your help