Centralized casino always request for KYC to be able to make withdrawals, between that also as a gambler if you don't want to have any issues on the casino you have to put in place some measures to prevent possible issues along the line, so as far as you set out to gamble, you have ready yourself to KYC and you should try as much as possible to go through all KYC so as not to have any issues when you hit the highest multipliers and want to withdraw your jackpot winning just like in your case.