PowerPort Atom III not charging

just bought this charger to use with my powerport speed 20k power pack. started out at 3 steady and one flashing light (I had previously partially charged power pack with another charger). after hours of charging, sent to 2 steady and one flashing. using the usb c connection on the charger. any idea whats going on?

The powerbank is most likely in output mode.

I’d check the cable you are using