The Callback URL or Verify Token couldn't be validated. Please verify the provided information or try again later - amazon-ec2

Question

I have been following the facebook bot setup guide and have setup a callback url that is running on an EC2 instance.
I am getting an error (see title of this) when trying to validate the callback url and verify token.
https://360.finance:1337/webhook is my webhook and the verify token is the same in my environment variable and in my facebook setting.
I set up SSL using LetsEncrypt and from what I can tell, the SSL is not showing as self signed so it looks to be working correctly (please note I'm new to all of this)
Checked at https://www.ssllabs.com/ssltest/analyze.html?d=360.finance&hideResults=on and all looks correct.
I have also included the facebook page token as an environment variable and included in my index.js file
I have tested netcat / telnet into that port on my ec2 ip and it is succeeding

Answer 1

You must return an http response of the hub.challenge token as a plain text.

Answer 2

We need to update the following on Facebook app settings page before adding The Callback URL or Verify Token.
Privacy Policy URL
Category
App Icon (1024*1024)
Its weird that facebook doesn't point our exact error.

Answer 3

check you callback server, if it is running or not ?
the callback and token comes from your server.

Answer 4

For python users you need to use a dot not underscore. I don't get it when I use the underscore version Facebook API cant access challenge but when I replicate the same GET request with postman I can access the challenge.
# Wrong way
challenge = request.GET['hub_challenge']
# Right way
challenge = request.GET['hub.challenge']
return HttpResponse(challenge)

Answer 5

Do not use ngrok or localtunnel.
I tried both, with no luck.
If you really want your local dev server to authenticate - you can port forward over ssh to your public faced server.
ssh -R 4000:localhost:4000 root#your-server-ip
This way you can setup nginx to reverse proxy 443 to 4000 and handle ssl with certbot
sample config for nginx reverse proxy (before running certbot)
server {
server_name my-own-domain;
root /usr/share/nginx/html;
index index.html index.htm;
listen 80;
location / {
proxy_pass http://localhost:4000/;
}
}
So you "only" need:
Your own domain
Your own server
nginx
certbot
SSH Server
And now you have your own private ngrok replacement