Fast Passes Sold Out?

I am going to Kings Island for the first time on the 19th, but it won’t let me buy them for that date online/it is greyed out. Is there an event or something I don’t know about that weekend? Or did everybody want to buy fast passes for that day haha. Would love to know if I could possibly still buy them in-park that day or if I am SOL. Never really had that issue at my home park (Cedar Point), so curious if you guys know anything.