Because I frequently upload all my assets between my 3 group accounts, I’m constantly logging in and out of accounts of Studio.
If I attempt to publish a game (without specifying, just clicking “publish”) it will present a 500 internal server error because I’m logged into a different account that studio doesn’t recognize as already having the place saved, it can’t overwrite something that doesn’t exist.
Log into the account that you loaded the place from and this should fix your issue.