Amazon web services – AWS Lambda Function URL – CORS Allow origin is not working properly

I am trying to allow requests to my Lambda Function URL only from my specific URL and only for POST methods.

Here is my Lambda Function URL configuration:

Here is the Lambda function content:

import json

def lambda_handler(event, context):
    # TODO implement
    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!!')
    }

Problems:

1. When I go to the function URL on my browser I see "Hello from
   Lambda!!". Considering it is a GET call I shouldn’t see the result
   right?
2. When I call the function URL with HTTP POST method from my Angular App (origin: localhost:4200), I am getting CORS error "No ‘Access-Control-Allow-Origin’ header is present on the requested resource." But I added that header to my request as shown in the screenshot below:

I tried ‘Access-Control-Allow-Origin’: ‘*’ as well but it didn’t work.

What am I doing wrong here?