I hope there will be kind of "Christmas Contest" that will be coming as we approach the holiday season. 
I'm not sure about contests, but many casinos and other platforms tend to have Christmas promotions at this time of the year. MonkeyTilt do have some ongoing promotions, but maybe another one, specifically about Christmas could be great for gamblers who regularly gamble on the platform.
What does CAO mean? Casino Administrative Organization? Does it refer to a regulatory body or an internal system or authority regulating games?
I have never heard of that organization. I have even Googled it but couldn't find any information about such an organization. I also tried finding a location abbreviated "CAO", but I could find nothing. I guess only the support team can explain what that means. From the error text, it looks like it is a geographical restriction, but confirming it from the official source is always better.
Even if it's a geographical restriction, it's probably from the game provider and not the platform itself, I believe.