Cloudflare tunnel not working for one specific Subdomain

I am using the cloudflare tunnel to redirect some subdomains to my local network. All of them are working fine, except one. Since today browse.h-cloud.io does not resolve anymore. If i change the base domain or create a tunnel with another subdomain the server is reachable, so it has nothing to do with config.

Any ideas how to fix that issue?

It now magically works again. But I still want to analyze the root cause for it, any ideas?