The named tunnel example fails with x509: certificate signed by unknown authority

I'm attempting to get the simple named tunnel example working in a rapi homelab k3s cluster on my home lan. I've verified the tunnel on my mac now attempting to get it running in the cluster.

I'm getting this error message:

`error parsing tunnel ID: REST request failed: Get "https://api.cloudflare.com/client/v4/accounts/976950979e32e569298940bab05aab7a/tunnels?is_deleted=false&name=example-tunnel": x509: certificate signed by unknown authority`

Any pointers?

Start with the simple named tunnel example in the repository and reproduce it in the reported k3s homelab environment. Trace the request to the Cloudflare API and investigate why the cluster reports an unknown certificate authority. Done means the example can retrieve the named tunnel without the reported x509 error.

Written by the indexing model from the issue text.