I am concerned that your headers are not soldered in to the shield. Which may cause these symptoms.
Judging by this earlier post:
Do i actually need to solder the headers onto the chip itself? I figured since the header polls are touching the circular metal rims of the mp3 player shield, the shield would still get electricity.
He did not solder the pinheaders to the shield. Yes, you need to solder the pinheaders to the shield.
Sorry, I’m trying to play catchup on the forum posts.