EA play doesn't work on Gamepass
EA play games on Game pass does not work, I have both accounts linked and it keeps trying to link my accounts. Your app simply doesn't work with Game pass. I don't know why you even wasted your time making an app this way, this issue has been going on for months. No way you haven't known about it.
This error usually means you're logging into the EA app with the incorrect login details. You need to sign in with the same EA account that your gamertag is linked with- to verify if you're on the incorrect account, you can look over your EA Connections tab here. If you're not seeing your gamertag listed there, that means you're logging in using the incorrect EA account.
You can also check which EA account you need to be logging in with by following the steps here to find out which email is tied with your account.