I have solved!!! 
The problem was due to the LDAP object classes.
This field is subtle but very important. You should fill it with all of the LDAP object classes that you will use in Plone and that make up your user objects in your Directory. I have solved by filling this ones:
organizationalPerson,zimbraAccount,amavisAccount
After this configuration,you have to set the LDAP schema Attribute, in the ZopeManagementInterface accordingly.
I have added this ones:
cn Canonical Name fullname No
mail Email address email No
sn Last Name No
uid User id No
ZimbraAccountStatus ZimbraAccountStatus No
zimbraId ZimbraId
It was simple 
Regards Elisa