Delegating nameservers failed. Why do they say No-IPs DNS server are not authoritative?
Some domain name registrars verify that DNS zone information is available on the new nameserver you are switching to. If you have just recently activated your No-IP+ or No-IP2 domain it can take up to 12 hours to become live on all of our DNS servers. You should try processing the nameserver changes after 12 hours has passed. Many of the .de, .br, and .au registrars enforce this type of checking.