The localnet documentation describes a step creating a namespace: https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html/virtualization/networking#virt-creating-secondary-udn-namespace_virt-connecting-vm-to-secondary-udn. This namespace would not be matched by the CUDN created in the step above. The VM created later in the procedure uses a different namespace too.

4.19+

Docs

1. Go to https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html/virtualization/networking#virt-creating-secondary-udn-namespace_virt-connecting-vm-to-secondary-udn

The namespace here is not matching the namespace in the CUDN namespace selector. The example in the VM below is not using the just-created-namespace.

The namespace should be consistent