I am trying to add In-app purchases to my app. I tried to create StoreKit Configuration File but after checking "Sync this file with an app in App Store Connect" I wanted to pick my team but the only options I had were "None" or "Ad an account...". And answering upcoming question: Yes I have team. Please help.
You have to remove or sign in again Apple Developer account which have error. Here, Xcode -> Settings -> tab Account
To be precise it seems like in Xcode 15.3 the list is only populated when you're logged into all of your developer accounts. So if there's a popup in the Preferences pane that opens up when you click "Add an account...", just log in and you should be set. I was.
I had the same issue, and when I checked on my developer account list (I got multiple developer accounts) in my Xcode -> Settings -> Accounts I could see there is one account has a sign-in issue (the password was changed on the web, but forgot to sign in to Xcode.), I removed it and then StoreKit Configuration Teams populated when I tried it again. So, simply put, check your account section of Xcode settings, all the accounts (if you have multiple) should have been setup correctly.