When I had this problem, the site was showing a high traffic warning, so there could be a problem (unfortunately, I don't have a screenshot I had taken)
It may be a problem related to that
Altjough I doubt this would be the cause of the problem but I still find it interesting as I have never experienced this before. I never saw a high traffic warning on a casno website before. Or are you talking about the CloudFlare vetification page that appears in case there is a high traffic or too much load on the casino's servers?