Why is my battery not charging

Hi, So I ordered a new battery from iFixit and got everything.

Replaced the old battery and tightened the screws. The display started and everything is working fine but the battery won't charge. I have used the wall outlet adapter to check and there is not even a flicker.

I am wondering if the connector marked 3 is related to this as I was having some issues pushing it in properly?

TIA