Why won't my MacBook turn on without being plugged in?

I bought the repair kit for the 2017 MacBook Pro and was able to install everything with virtually no hiccups, except for the antenna assembly rising and causing the back plate to bow. But the primary issue is now the computer turns on and functions well, but won’t do so without being plugged in. When I go to check the status of the battery’s health, it reads <DNL> and won’t let me show the percentage of the battery’s charge in the menu bar. I also tried resetting my SMC, but nothing changed. Does anyone know what I can do to fix this, or even what might be wrong? Thank you!