Not sure my Power Core is charging properly

Hey all, just bought an Anker Powercore Slim 100000, however, it doesn’t seem to be charging correctly or fully and the manual is no help at all.

So at least according to other posts on here, when it is fully charged, all 4 blue lights should light up solid. But when I plug it in to charge, it quickly goes to all 4 lights, then back down to 2, then just shuts off. I don’t know if it is only charging half way, or not at all, or what.

Am I mistaken about what lights should flash and all?

Would appreciate help here, as this is my first ever battery bank and I’m not sure if I am just misreading something.

Thanks!