In a Schema 1 scenario, if two DC Tree nodes exist, dc=sesta and dc=sesta2, both referring to the user/group base node o=sesta, then you must specify the canonical domain name as follows:
dn:dc=sesta,dc=com,o=internet inetDomainBaseDN:o=sesta.com
dn:dc=sesta2,dc=com,o=internet inetDomainBaseDN: o=sesta.com inetCanonicalDomainName:sesta.com