[HELP] Individual user cannot submit

I have a brand new forum with only 9 users. I have 1 user who is in the same group as everyone else and can access the arcade. However, he cannot submit his score. At the end of every game he gets, "this score will not be submitted." This just started today. Yesterday he was able to play games and submit his scores with no problems and nothing has changed between yesterday and today.

He is logged in and not timing out for inactivity.

Thoughts/advice?