Domain Not working after nameservers change

Hi there,

I currently host my site on Hostinger, and want to use Cloudflare for DNS service. After I changed the nameservers, Add DNSSEC on Hostiner account, I received the email saying that my site is protected by Cloudflare now.

But I could NOT visit my site… neither all my subdomains…

After I deleted my domain in cloudflare, and changed the nameservers back to hostinger’s. I can visit my domain and subdomains again!!!

Anyone know why?

Thanks for any advice and suggestions~
Simon