Facebook Messenger Callback URL fails

I am attempting to create a very basic bot to simply get everything wired up. I am developing locally, so I also created a local webook using ngrok.

I have to admit that I am stumped when following the documentation on the Facebook connector, found here. I attempted both the run script and through python options, both with the same result.

Where it landed was that Facebook could not authorize my webhook under the settings for the Messenger Product associated with my app. This is occurring when I am attempting to Verify and Save the webhook.

The error:


What’s more curious is that I also received the same error (challenge not successful) when following the instructions on the same page for Slack.

That said, when looking at the requests coming into my local server, ngrok is showing 200 on the validation requests.

Any help or updates to the docs to provide a novice like myself (in dealing with building Facebook/Slack apps) would be greatly appreciated!


As an update to this, I was able to get the example working as expected, only after I used a separate server setup to authenticate the callback. I found that example (though I had to hack it together) here:

That said, I would have expected this to be handled out of the box

What do you mean handled out of the box? If you provide the /webhook URL, the bot should work as is