Preventing lame delegation hijacking https://help.ns1.com/hc/en-us/articles/360063594293-Preventing-lame-delegation-hijacking
Best practices to prevent lame delegation hijacking (NS1.com)
NS1 has controls in place to prevent lame delegation hijacking. To enhance zone ownership security in the Managed DNS platform, NS1 puts a hold (creates this zone in an internal account) on zones delegated to NS1 name servers but that did not previously exist in the platform. This hold prevents any hijacking of these zones by malicious actors between the delegation and zone creation steps.
NS1 recommends that you create zones within the platform before you delegate them to avoid risk and to prevent zone collision interruptions. As a best practice, you should always ensure that your TLD delegations are current and that they point to the correct provider.
NS1’s controls can make it appear as though a zone already exists on NS1’s platform, creating a “zone ollision.” To fix this issue, contact NS1 Support to investigate and free up the zone for creation in your account.