Tradable player turns into Untradeable

I’m pretty frustrated right now because I saved up 300,000,000 coins to invest in a 113 Gravenberch TOTY card on the market and after I bought it I went back into my players and it’s listed as an untradable one now. At this point I don’t even want to buy anything in the market until this gets fixed because all your coins could be lost in an instant.