Hi, @mkuehb. I checked and the DNS zone does not exist under Netlify’s NS1 account. We have a support guide with instructions about how to resolve this here:
To summarize, either:
Find the source the DNS zone (which could be Namecheap.com itself similar to the Name.com issues) and delete it there.
or:
Create a support ticket with NS1 (which requires creating a free account there) and their support team can delete it.
If there are other questions, please reply here anytime.