Your charger doesnt like what it is seeing and wont charge the battery. If you ran or discharged the battery too much one of your cells could have droped below LVC point making the charger think that the battery is damaged. It is a safety protocall. How did the battery drop below LVC? Was the battery hot last time you discharged it? You need to get the adapter for the balancer, that is a must and probibly the cause for this issue. The one cell could be way out of balance but not be damaged there are ways to fix that, although no one would recoment it! Until you get a balancer or get some voltage readings per cell, I wouldnt touch it!