Cloudflare registrar nameserver issue

I got my domain through cloudflare, but it wants me to update my nameservers, but I cant since they are already the ones cloudflare wanted me to have. I try to add new nameservers through my DNS records, and it tells me this: "Content for NS record is invalid. NS records at the Apex have must not overwrite assighned nameservers."

What do I do? I cant use my domain for my icloud email anymore!