Big issue with NS record changes and paid plans

I have a site here on Cloudflare. Recently a client of mine switched domain registrars and thus the NS records changed, but all of the A,CNAME,TXT records were left exactly as is. The site continued to work normally despite the NS records not pointing to Cloudflare. We were told this is because we are on the paid plan.

The problem is that when we asked the client to change the NS records to the Cloudflare ones, the site broke completely and returned a 1001 error. The proxy layer also seemed to be non-functional. No matter what we did, we couldn’t remediate the issue, so we had to create an entirely new Cloudflare site, copy all of the settings in manually, and then have the client switch the NS records. Only at that point did it start working again.

Seems like something worth looking into!

This is not normal. Changing registrar should make no difference to the configured nameservers. Something else was changed.

There are a number of causes of error 1001. Do you have a screenshot of the error, or can you share the domain?

Are they using a CNAME setup?

To my knowledge, when the client switched registrars to MarkMonitor, someone or something did change the name servers away from Cloudflare, but all other records were left in place, including the our proxied CNAMEs.

Here is a screenshot of the error that we saw.

That website is loading for me. Have you tried from different devices in different locations? Over cellular?

The issue has since been fixed because we created an entirely new Cloudflare site configuration and repointed the name servers to the new one because the old Cloudflare site configuration essentially appeared to have become “corrupt”. For example, the proxies stopped working entirely, which meant that the edge certificates weren’t there, the WAF wasn’t there, the CDN wasn’t there, etc.