Leaderboards in my game do nto work. Instead of pulling up my leaderboard in the game, it pulls up Acheivements and Challenges. Im assuming this is because it can not find my leaderboard, so it's pulling up like a default Game Center screen. So, when I go to App Store Connect and click on my leaderboard under Features -> Game Center, it says "We can't process your request. Go back to where you were and try again. If the problem continues, contact us."
I'm having the exact same issue. Would really love to know how to resolve it.
Turnera30, I contacted support and it took about a week, but they got this fixed for me. They didn't say what was wrong, but I suspect what they fixed for me may have fixed it for you as well. Good luck!