This zone’s nameservers are not on Cloudfloare. They point to
Name Server: NS1.DENTISTRYTODAY.INFO
Name Server: NS2.DENTISTRYTODAY.INFO
There are no glue records for those hostnames and can’t be resolved. If you wish to use Cloudflare for this zone the nameservers need to be pointed at Cloudflare.
If your “programmers” changed the name servers to something off the Cloudflare network then they should have set up DNS servers to handle the authoritative DNS on behalf of your domain.
You are currently without a DNS on your domain. You should come back to Cloudflare or ask your “programmers” to solve their problem.
They should point the nameservers for that zone to nameservers which are authoritative for that zone. It’s fine if they don’t want to use Cloudflare, but whatever nameservers they choose, need to be properly configured and at the moment they are not. If they didn’t have a good reason to change them, they should change them back.