I started getting an error in my CI process Please enter Username: error: EOF when running kubectl commands. The kubectl version matches the cluster version, and I can run the same commands fine from my machine with the same configuration shown by kubectl config view.

Here are the logs:

+ kubectl config view
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: REDACTED_FOR_QUESTION
  name: REDACTED_FOR_QUESTION
contexts:
- context:
    cluster: REDACTED_FOR_QUESTION
    user: REDACTED_FOR_QUESTION
  name: REDACTED_FOR_QUESTION
current-context: REDACTED_FOR_QUESTION
kind: Config
preferences: {}
users:
- name: REDACTED_FOR_QUESTION
  user:
    client-certificate-data: REDACTED
    client-key-data: REDACTED
++ echo 'Starting Kube proxy - port is 8001'
++ set +e
++ echo 'using kubectl'
++ sleep 1
++ kubectl proxy --port=8001
error: EOF
++ cat backingfile
++ rm backingfile
++ set -e
+ echo Starting Kube proxy - port is 8001 using kubectl Please enter Username:
Starting Kube proxy - port is 8001 using kubectl Please enter Username:
+ kubectl version
Please enter Username: error: EOF
Exited with code 1

What I am doing in my script is the following:

  echo "using kubectl"
  kubectl proxy --port=${KUBECTL_PROXY_PORT} > backingfile &
  sleep 1 && cat backingfile && rm backingfile
  set -e

As this allowed me to launch kubectl in the background but still get the logs of the command.

What is causing this error and how can I run the command successfully again? Please enter Username: error: EOF