Casino Luck is regulated by Malta and powered by Netent casino games. Both Malta and Netent do not accept citizens from the United States of America.
I sent an email to the Casino Luck support to get a clear explanation. Here is their answer :
We can unfortunately not accept any US citizens to play on our site. You need to be a citizen of another country to be able to register an account.
As part of the US gambling law, Casino Luck preferred to step back from the US Markets. However, some online casinos still continue to accept US citizens. Check our top 3 US Casinos.
Technically, you could play to Casino Luck if you signed up from abroad. For instance if you are in vacation in Panama or in Colombia, you could play to Casino Luck while you drink your Pina Colada. However, you should not use a US address and an american credit card (from Chase for instance).
This is the same problem as "signing-up from abroad". You could use a VPN to play to Casino Luck, but you would need to have a real address outside of the US (with rent receipt at your name for instance). If you have your mother abroad, for instance in the Sweden, it could work. Otherwise, in case you win a $6,000,000 jackpot, Casino Luck could block your funds..
We know that Bovada is currently accepting US citizens. It is powered by Top Game software and offers a nice welcome bonus.