Trying to add dkim data to my server, I receive this error:

Code:
zimbra@linux2:~$ /opt/zimbra/libexec/zmdkimkeyutil -s init-s -u -d fantasys.it
Error: Domain fantasys.it doesn't have DKIM enabled.
zimbra@linux2:~$ /opt/zimbra/libexec/zmdkimkeyutil -s init-s -r -d fantasys.it
Error: Domain fantasys.it doesn't have DKIM enabled.
zimbra@linux2:~$ /opt/zimbra/libexec/zmdkimkeyutil -s init-s -a -d fantasys.it
Error: Failed to update LDAP: LDAP_CONSTRAINT_VIOLATION
I cannot find errors in error logs.
I deleted the domain and I created it again but I've got the same error.