It looks like max bets have not been enabled in settings for you to use.

Follow these steps:
1. Click the orange circle on the side.


2. Click SETTINGS


3. Enable


In most of their games, Max Bet is 0.5 Bitcoin

but in Chuck -A- Luck and Numbers the max bet is 0.18181818 and 0.16666666 respectively (I just don't know if that fix or maybe it still changes)