Power core slim 10000 PD drains Nintendo switch battery

I recently bought a Powercore slim 10000 PD but I’m having problems with my Nintendo switch. I’m using the cable provided with the power bank and the PD Port, but the Nintendo switch is charging the power bank, when it should be the power bank charging the console.
Does anyone have any suggestions? I tried with my mobile phone and it does not happen.

You have to press the button on the batterypack Before plugging anything into it, otherwise it will draw power instead of outputting it