"Missing Authentication Token error"

Hi I am having an issue that is drivin me crazy and I cant solve. I am new to using chalice to please bear with me.
When i deploy and run chalice the following code works when I open up a web browser and use the URL:
@app.route('/')
def index():
return {'hello': 'world'}

it shows hello world.

However, when I try to set it up to receive a POST the web browser shows "Missing Authentication Token"
@app.route('/stockalert', methods=['POST'])
def stock_alert():

return {
"message": "An alert occured"
}

And yes I did add stockalert to the end of the URL and it still didnt work.
Anyone have any idea why this is happening?

Start by comparing the deployed root URL, which works in a browser with GET, with the /stockalert route and its declared POST method. Verify the request uses POST rather than a browser GET and confirm that a correctly formed POST to the deployed /stockalert URL returns the alert message.

Written by the indexing model from the issue text.