I'm trying to subscribe to private messages sent to my Facebook page.
You can subscribe to this callback by selecting the message field when setting up your webhook.
https://developers.facebook.com/docs/messenger-platform/webhook-reference/message?locale=en_US
There is no field "message". Do they mean "messages"? The screenshot on this page does not show a "message" field either: https://developers.facebook.com/docs/messenger-platform/webhook-reference?locale=en_US
When I subscribe to "messages" I don't receive any event when someone writes a private message. When I subscribe to "conversations" I receive updates, but they only contain the "thread_id" and not the content of the private message.
What do I have to do to receive the message content in an update?