Ngrok errors '502 bad gateway'

Question

Quite new to using any sort of Web App stuff, and I\'ve been trying to slowly build a Facebook Messenger Bot. When I try to use ngrok I can\'t visit the address I\'m given,

Answer 1

Just as @njzk2 should have said, if you don't have a web server running so it cannot work. I would like to make it clearer to you, if you are still confused.

What ngrok does, is to make your local server (running on localhost) to be available to the outside world (rest of the internet). On its own, it is not a web server. So for your bot development you need to have a web server running on a defined port (which in your case is 5000). Then you can point ngrok to this port so that it will redirect requests sent to your public address to the program running on that port. The web server will then accept and handle requests from Facebook