FAQ: 2018062 (#100) The URL provided is not whitelisted for messenger extensions

Are you using Question Step - Date/Datetime step in Agency Account with white-label domain?

If yes, you can choose one of the following solutions to solve this:

1. reconnect your Facebook account by heading to the Facebook channel on your dashboard, then hit the "Reconnect" button.

2. if the above solution didn't add the domain automatically, please manually add "bot.dfktv2.com" to your whitelisted website in your Facebook bot, see the screenshot about how to implement it: