Miguel Jinez wrote:

I have SERVERID 1, SERVERID 2 and SERVERID 3 for each master configuration

On list please. See below.

can you try Multi-Master and not MirrorMode:

http://www.openldap.org/doc/admin24/replication.html#N-Way%20Multi-Master

You don't have:

serverID 1 LDAP_URI