Insecure docket registry

Hi, I have an insecure docker registry (installed via arkade install docker-registry) in a private k3s cluster (installed via k3sup) and I cannot pull images from that from my Deployments.
On the master node I have this config active:

$ cat /etc/rancher/k3s/registries.yaml 
      - ""
      username: admin
      password: xxxxxxxxxxxxxx is one of the workers; on the port 5000 I can successfully log in, push and pull images.

On all machines, I have adapted the docker configuration:

$ cat /etc/docker/daemon.json 
  "insecure-registries" : [""]

On all nodes, docker info lists the insecure registry:

 Insecure Registries:

On the master node, in /var/lib/rancher/k3s/agent/etc/containerd/config.toml I can see that the config from registries.yaml sort of “arrived”:

$ cat /var/lib/rancher/k3s/agent/etc/containerd/config.toml

  path = "/var/lib/rancher/k3s/agent/containerd"

  stream_server_address = ""
  stream_server_port = "10010"
  enable_selinux = false
  sandbox_image = ""

  snapshotter = "overlayfs"

  bin_dir = "/var/lib/rancher/k3s/data/ad8f0f93ebb9db5c507884fcdec249d73dd348293dac194e01462c57815cca46/bin"
  conf_dir = "/var/lib/rancher/k3s/agent/etc/cni/net.d"

  runtime_type = "io.containerd.runc.v2"


  endpoint = [""]

  username = "admin"
  password = "xxxxx"

Unfortunately, kubectl describe deployment xxx doesn’t seem to be impressed by my configuration attempts, although everything has been restarted.

  Type     Reason     Age   From               Message
  ----     ------     ----  ----               -------
  Normal   Scheduled  6s    default-scheduler  Successfully assigned mydeployment/mypackage-deployment-56fffb99d-7zqp4 to nuc2
  Normal   Pulling    5s    kubelet            Pulling image ""
  Warning  Failed     5s    kubelet            Failed to pull image "": rpc error: code = Unknown desc = failed to pull and unpack image "": failed to resolve reference "": failed to do request: Head "": http: server gave HTTP response to HTTPS client
  Warning  Failed     5s    kubelet            Error: ErrImagePull
  Normal   BackOff    4s    kubelet            Back-off pulling image ""
  Warning  Failed     4s    kubelet            Error: ImagePullBackOff

What else can I try?
Thank you in advance.