YAML - Validation error during deployment using Yaml config file

I'm following this Microsoft Tutorial to create a Windows Server container on an Azure Kubernetes Service (AKS) cluster using Azure Cli. In the Run the Application section of this turorial, I get the following error when running the following command to deploy the application using YAML config file:

kubectl apply -f sample.yaml

error: error validating "sample.yaml": error validating data: apiVersion not set; if you choose to ignore these errors, turn validation off with --validate=false

Question: As shown in the following sample.yaml file, the apiVersion is already set. So what this error is about and how can we fix the issue?

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample
  labels:
    app: sample
spec:
  replicas: 1
  template:
    metadata:
      name: sample
      labels:
        app: sample
    spec:
      nodeSelector:
        "beta.kubernetes.io/os": windows
      containers:
      - name: sample
        image: mcr.microsoft.com/dotnet/framework/samples:aspnetapp
        resources:
          limits:
            cpu: 1
            memory: 800M
          requests:
            cpu: .1
            memory: 300M
        ports:
          - containerPort: 80
  selector:
    matchLabels:
      app: sample
---
apiVersion: v1
kind: Service
metadata:
  name: sample
spec:
  type: LoadBalancer
  ports:
  - protocol: TCP
    port: 80
  selector:
    app: sample

Issue resolved. The issue was related to copy/paste to Azure Cloud Shell. When you copy/paste content to vi editor in Azure Cloud Shell and if the content's first letter happens to be a then following may happen:

when opened vi in read mode, then by pasting, the first a may put user in edit mode and may not actually get that a inserted in the editor. So, in my case the content was pasted as follows (I'm only showing the first few lines here for brevity). So you notice here a was missing in the first line apiVersion: apps/v1 below:

sample.yaml file:

piVersion: apps/v1
kind: Deployment
metadata:
…..
...