10s4p only charging 60%...bad BMS? Bad pack?


My 10s4p is giving only 37.8 V on full charge and is only showing as 61% charged. There’s a bad pack or a bad connection. I’ve used multimeter on whole pack and the issue starts at B6. So, am I looking for a bad connection between B5 and B6, or a bad connection between B6 and the BMS?

I’ve found that a pack in the middle isn’t showing any voltage. The packs either side are OK. What would cause this!!? And, how do I fix it!?