I updated the namserver to cloudflare at the register side. I checked the nameservers are corret and DNSSEC is turned off. I checked the WHOIS and it correctly reflects the cloudflare nameservers. It has been more than 24-hr why it is still pending?
What feature, service or problem is this related to?
Make sure you have spelt your domain correctly when adding it to Cloudflare and you have selected a plan (even if free). Check on the overview page for the domain.