MySQL connection problems after fresh install

==== Required information ====
- iRedMail version: 0.8.6
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Linux/BSD distribution name and version: CentOS 6.5
- Related log if you're reporting an issue:
====

Hi,

I have just installed iRedMail but it keeps giving me database connection errors, on RoundCube and iRedAdmin.

Where should I look for? There are no databases related to iRedMail on my system, but iRedMail was installed.

Thanks!