I do not know which balance connectors are mounted on your 14 cell Lipo. But these must fit into the charger's balancing input. If not, the balance connectors on the Li-Po must be replaced or an adapter cable is required.
Remember that the two balancer connectors that are placed in the charger look the same, but are not electrically equal. Incorrect placement causes short-circuit with damage to the balancer wiring and possibly also to the print tracks of the charger.