Incorrect k8s deployment file – Nginx

I am following Cloud Guru K8S course and have issues with the template they provided. I can’t see what’s wrong.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: blue-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: bluegreen-test
      color: blue
  template:
    metadata:
      labels:
        app: bluegreen-test
        color: blue
    spec:
      containers:
      - name: nginx
        image: linuxacademycontent/ckad-nginx:blue
        ports:
        - containerPort: 80

When I run

kubectl apply -f my-deployment.yml

I get

error: error parsing blue-deployment.yml: error converting YAML to JSON: yaml: line 4: found character that cannot start any token

What’s wrong with this template? It’s nearly identical to the official example deployment definition https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#creating-a-deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80