Display screen black (no Apple logo/chime) after installing new batter

I just replaced a new battery on my MacBook Retina (12 in early 2015) after following the steps exactly as how they are listed on this article (even bought their kit).

Remplacement de la batterie du Macbook Retina 2015

I triple checked all the connections and they are well connected and I don’t see any damage (not that I think I did because I was very careful).

I also bought the recommended low voltage USB-A to USB-C cable. When I plug the cable in, the display screen is still off (black) no chime sound or the battery charging symbol. It’s like the computer is completely dead. Doesn’t power on when I press the power button. Nothing. Could it be a faulty battery (bought it from ifixit).