404 Not Found when using Flask and Ngrok for http://127.0.0.1:5000

Question

Complete beginner in flask, ngrok and twilio. I ran this piece of python code to create a flask app for twilio :

from flask import Flask, request, redirect
from twilio.twiml.messaging_response import MessagingResponse

app = Flask(__name__)

@app.route("/sms", methods=['GET', 'POST'])
def incoming_sms():
    """Send a dynamic reply to an incoming text message"""
    # Get the message the user sent our Twilio number
    body = request.values.get('Body', None)

    # Start our TwiML response
    resp = MessagingResponse()

    # Determine the right reply for this message
    if body == 'hello':
        resp.message("Hi!")
    elif body == 'bye':
        resp.message("Goodbye")

    return str(resp)

if __name__ == "__main__":
    app.run(debug=True)

It was hosted on http://127.0.0.1:5000

I then ran "ngrok http http://127.0.0.1:5000" which create an ngrok link, but when I used it I get 404 not found. What is causing this issue and how can I fix it ?

UPDATE: http://127.0.0.1:5000/sms does not work, shows blank page

Answer 1

1. Run ngrok 5000
2. Here is the flask code for generating, sending and validating OTP:

@app.route('/getOTP', methods=['GET', 'POST'])
def getOTP():
    mobNum = request.get_json().get("mobNum")
    length = len(mobNum)
    val = 0
    if length == 13 :
     val = getOTPApi(mobNum)
    elif length == '' or length < 12:
        message = "Failure"
        print(message)
        return message
         {'ContentType':'application/json'}
    if val:
          message = "Success"
          print(message)
          return message
    
    else:
        message = "NaN"
        print(message)
        return message
    

@app.route('/validateOTP', methods=['POST'])
def validateOTP():
    otp = request.get_json().get("otp")
    length = len(otp)
    if 'response' in session:
        s = session['response']
        
        if s == otp:
          message = "Success"
          print(message)
          return message
        elif length == 0 or length < 6:
          message = "NaN"
          print(message)
          return message
        else:
          message = "Failure"
          print(message)
          return message
    session.pop('response', None)  
    
    
def generateOTP():
        return random.randrange(100000, 999999)  
    
def getOTPApi(mobNum):
    account_sid = 'XXXxxXXXXXX'
    auth_token = 'XXXxxXXXXXX'
    client = Client(account_sid, auth_token)
    otp = generateOTP()
    session['response'] = str(otp)
    body = 'Your OTP is ' + str(otp)
    message = client.messages.create(
                              from_='+1123456789',
                              body=body,
                              to=mobNum
        
                                   )
    if message.sid:
        return True
    else:
        return False