I have a simple web app to message (using Twilio API) selected respondents with the following code:

app.py

client = Client(account_sid, auth_token)

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/send_sms',methods=['POST'])
def send_sms():
    message = request.form['message']
    selected_groups = request.form.getlist('groups')
    selected_secretariat_member = request.form.get('selected_secretariat_member')
    # more code ...
    return redirect(url_for('index'))

templates/index.html

<div class="container mt-5">
    <h1 class="text-center">Send Mass SMS</h1>
    <form method="post" action="{{ url_for('send_sms') }}">
      <div class="form-group">
        <label for="message">Message</label>
        <textarea class="form-control" id="message" name="message" rows="3" required></textarea>
      </div>
      <div class="form-group">
        <label>Select Groups</label>
        <!-- Groups -->
      </div>
      <button type="submit" class="btn btn-primary">Send SMS</button>
    </form>
</div>

I was using the live server provided by the VS Code live server extension I believe. When I clicked on submit for my form, I received a 405 Error. When I look at the network section in developer tools, the Response Headers has a row stating which methods are allowed and only GET, HEAD, OPTIONS are allowed. I tried other solutions people had proposed on SO such as:

1. Adding the following to web.config

<system.webServer>
  <modules>
    <remove name="WebDAVModule" />
  </modules>
  <handlers>
    <remove name="WebDAV" />
  </handlers>
</system.webServer>

2. Defining the methods before the index() function

@app.route('/', methods=['GET','POST'])
def index():
    return render_template('index.html')

3. Checking the handler mappings to see if POST is part of their allowed Verbs

4. Adding GET to the methods for send_sms()

app.route('/send_sms',methods=['GET','POST'])
def send_sms():

I am really confused on what to do. I used to have this error when learning HTML Forms and php but I brushed it off as I didn’t have a dedicated web server. However this seems to be a problem with the methods in general. Appreciate the help.