We use SOGo with the LDAP connection and let us show the contacts in the address book (sogo.conf with isAddressBook = YES). If the LDAP attribute "cn" contains a special character such as "(", the error message "Not Found" is displayed when accessing the address book entry.

Our relevant sogo.conf settings are as follows:
CNFieldName = displayName;
IDFieldName = cn;
UIDFieldName = sAMAccountName;
bindFields = (sAMAccountName);