Are you using Nethserver 7.5, or a plain CentOS installation? If the latter, this forum really isn’t the place for your questions.
I’m plain CentOS installation. Im’ sorry, I didn’t know
Nethserver Horde implementation works with AD/LDAP (addressbook) but IMAP login is used.
Thank you for your suggestion but at this time I have to do only with CentOS, maybe later I will try the Nethserver. The Horde installation and configuration of the for CentOS is the same as Nethserver, I will see you steps with more careful and compare with my configurations.