Standard security check is a common thing here especially if it is your first withdrawal or you use different withdrawal address (if it is not your first withdrawal). Active players can get the same delay as well, it can be related to the game providers (if you play 3rd party games). No need to worry, you'll get your money eventually if there is nothing wrong with your account.
That is something good, I've tried a few services which didn't have any kind of security system, all gambling services must have something to prevent people withdrawing wrong, Ip check, amount, and more.