Thank you for watching The Game Awards on Mixer, you have received your MixPot! Find your Sea of Thieves Obsidian Cannon in the Shipwright’s chest in-game, and redeem your new Forza Horizon 4 Limited Edition Festival Jacket by navigating to the Gifts tab in-game.
Mine just showed up in my inventory, I did not have to claim anything.
I got a message yesterday when I logged in to say a new item had been added to my profile which was the jacket.
I got the message but there was no jacket in the gifts tab.
Look two posts above yours.