The Kubernetes Book

Set your kubeconfig back to using the default Namespace. If you don’t do this, future commands will automatically run against the deleted shield Namespace and will fail.

$ kubectl config set-context --current --namespace default
Context "k3d-tkb" modified.

Another way to introspect a running Pod is to log into it or execute commands in it. You can do both of these with kubectl exec. The following example shows how to execute a ps aux command in the first container in the hello-pod Pod.
$ kubectl exec hello-pod -- ps aux