I have the same problem using both itch.io AND Gamejolt. Both don't like my Gamejolt game token. Whilst logged into Gamejolt and playing from Gamejolt, progressed isn't saved. Tried using the login feature (I am presented with the login option and New Game option - even if logged into Gamejolt. I even see greyed text "logged into Gamejolt..." in the lower right of the game screen whilst login screen is open. Not sure that made sense. :-) I suspect it's an API issue.