Replaced the battery. Not charging.

Hi.

I just replaced the dead battery on my iPhone 6s Plus, and installed a battery that is made by a third party company. It did turn on and the phone works perfectly fine. (Before the replacement, it was stuck in the drained battery page but now it works ok) However, when I charge the phone, it would not charge itself. I know for sure it is not the fault of the cable because if I plug the cable when the phone is off, it automatically turns on the black Apple logo on the white background and boots. Do you have any idea why this is the problem?

Thank you!!