dropbox.exceptions.AuthError: AuthError('adf0b24714c641a5b3dfcd68573db5e4', AuthError('invalid_acces

I am working on a notification app linked to a business account via a webhook to get notified when any of the team members edit files in certain folders.  Attached below is the code, deployed on Heroku

 

 

import os
from dotenv import load_dotenv
from dropbox import Dropbox
from flask import Flask, render_template, session, Response, request, abort
import hmac
from hashlib import sha256
import json
import threading
import sendgrid
from sendgrid.helpers.mail import *
import redis
from dropbox.files import DeletedMetadata, FolderMetadata, WriteMode, FileMetadata
from dropbox.users import FullAccount

load_dotenv()

ACCESS_TOKEN = os.environ.get('ACCESS_TOKEN')
APP_KEY = os.environ.get('APP_KEY')
APP_SECRET = os.environ.get('APP_SECRET')
EMAIL_USERNAME = os.environ.get('EMAIL_USERNAME')
redis_url = os.environ.get('REDISTOGO_URL')
redis_client = redis.from_url(redis_url, decode_responses=True)
main_folder = 'Career Consulting Real'
subfolder_list = ['eng101', "mat101"]

app = Flask(__name__)
app.secret_key = os.environ.get('FLASK_SECRET_KEY')

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

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

@app.route('/webhook', methods=['GET'])
def challenge():
    resp = Response(request.args.get('challenge'))
    resp.headers['Content-Type'] = 'text/plain'
    resp.headers['X-Content-Type-Options'] = 'nosniff'
    print(resp)
    return resp

@app.route('/webhook', methods=['POST'])
def webhook():
    # '''Receive a list of changed user IDs from Dropbox and process each.'''

    #make sure this is a valid request from Dropbox
    signature = request.headers.get('X-Dropbox-Signature')
    key = bytes(APP_SECRET, encoding="ascii")
    if not hmac.compare_digest(signature, hmac.new(key, request.data, sha256).hexdigest()):
        abort(403)

    #print(json.loads(request.data))
    #print(json.loads(request.data)['delta']['teams']['dbtid:AAB_JmVTCr29MzCFLUPWLOP3ch-RdRv3Quo'])
    for account in json.loads(request.data)['delta']['teams']['dbtid:AAB_JmVTCr29MzCFLUPWLOP3ch-RdRv3Quo']:
        # We need to respond quickly to the webhook request, so we do the
        # actual work in a separate thread. For more robustness, it's a
        # good idea to add the work to a reliable queue and process the queue
        # in a worker process.
        threading.Thread(target=process_user, args=(account,)).start()

    return ''

def filter_notifications(entry):
    file_path_split = entry.path_display.replace(' ', '').lower().split('/')
    if file_path_split[1] == main_folder.replace(' ', '').lower():
        for subfolder in subfolder_list:
            if subfolder in file_path_split[2]:
                return True

def send_notification(message):

    send_grid_key = os.environ.get('SEND_GRID')
    sg = sendgrid.SendGridAPIClient(api_key=send_grid_key)
    from_email = Email(EMAIL_USERNAME)
    to_email = To("cdropboxchanges@gmail.com")
    subject = "A change has been made"
    content = Content("text/plain", message)
    mail = Mail(from_email, to_email, subject, content)
    response = sg.client.mail.send.post(request_body=mail.get())

def process_user(account):

    # cursor for the user (None the first time)
    cursor = redis_client.hget('cursors', account)

    dbx = Dropbox(ACCESS_TOKEN)

    has_more = True

    while has_more:
        if cursor is None:
            result = dbx.files_list_folder(path='', recursive=True, include_non_downloadable_files=True)
        else:
            result = dbx.files_list_folder_continue(cursor)

        for entry in result.entries:
            if filter_notifications(entry):
                if isinstance(entry, FileMetadata):
                    send_notification('File Metadat')
                elif isinstance(entry, DeletedMetadata):
                    send_notification('DeletedMetadata')
                elif isinstance(entry, FolderMetadata):
                    send_notification('Folder Metadata')
                else:
                    send_notification('Something happened, not sure what...')

        # Update cursor
        cursor = result.cursor
        redis_client.hset('cursors', account, cursor)

        # Repeat only if there's more to do
        has_more = result.has_more


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

 

 

When I run the code, I get the following error: 

 dropbox.exceptions.AuthError: AuthError('adf0b24714c641a5b3dfcd68573db5e4', AuthError('invalid_access_token', None))

However, the access token I am passing in is straight from the app on Dropbox.

Can you please advise what could be the problem that is causing this error?

Thank you