It's been a week since I'm having trouble with switching my .DE domain to work through Cloudflare. After registering at Cloudflare I got two dns servers
But my hoster (I got hosting and domains on the same account) refused to change my existing DNS servers to the Cloudflare ones. After a long conversation, the hoster changed the servers to
saying that it's not possibile to change them again to gail and mark. The hoster mostly replies that Cloudflare has no proper DNS records on their servers.
Can you explain, what is the root of such rescrictions ? Is there any special legal requirement for .DE domains?
After a few more days of talking, the issue was resolved. As I was told by the Cloudflare support, some European registrars require valid records to be present before you can change the DNS server for your domain. This is the case with the .DE domain. And that's where it went wrong when I first created my Cloudflare account. The cloudflare supported fixed it, everything is working fine now.
@HBruijn provided the link for Nameserver Predelegation Check for .DE domains, which was really helpful, because I had to call DENIC at first, thanks a lot.