My Ipad Air 4 is changed battery myself, but Cann't charge.

Hello.

I replaced the battery in my iPad Air 4 myself. When I connect the charger, the lightning icon(⚡) appears, but the battery does not charge. However, the battery doesn’t drain as long as the charger is connected. What could be causing the issue with the battery not charging?

I have tried both updating the software and performing a factory reset.