Hi, I'm not particularly sure about this, but something similar occurred for me a while ago—so you might want to give it a shot. This might happen if you are running a game based in Ren'Py while you have sandbox mode active. I've emailed itch.io for help, but I haven't gotten any back.
You should turn sandbox mode off; if you have it on. Alternatively, if you want to keep it on for other games, there is also an option to move the game out of the itch.io 'Games' folder. I hope this helps you!