"400 Bad Request cloudflare" when trying to update game details

I would like to play all my games in order from oldest to newest, and Lutris is very helpful in this regard by listing games by release year. However, some games are lacking their release year or other details on the web site. So I decided to add them myself.

But when I try to do so, after I hit the submit button, I get a " 400 Bad Request cloudflare" in my browser. I don’t get any error messages so I’m not sure how to continue from here.