It happens with our other portable devices. Check the cord for damage.
The ac adaptor or usb cable could be bad.
Dewalt 1400 jump starter won't charge. If your battery jump starter has a charge indicator light, make sure it is coming on. Metal powder coated clamps for durability. 120 psi digital air compressor (w/ auto shut off) and sure fit™ nozzle to inflate vehicle tires and sports equipment.
When wondering why your jump starter won’t charge you need to consider all the possibilities.