Some subdomains do not work for tunnels

Here I have a service that I am tunneling. When the subdomain is “uptime” it works, but if i change it to “blog” or “www” it suddenly stops working. Even if I wait a while.

I couldn’t embed images so they’re here https://imgur.com/a/BqDr3Ir

I tried these instructions https://developers.cloudflare.com/dns/troubleshooting/dns-probe-finished-nxdomain/

but they didn’t help