Building a custom UI to bypass the standard Messenger widget. Using the Guest API to send messages directly via the inbound Open Message endpoint. I’m passing the conversationId from the session creation response. Getting a 403 Forbidden error. The Authorization: Bearer token is fresh. Here’s the payload:
{
"text": "Hello world"
}
Checked the docs, but nothing mentions permission scopes for raw guest message posting. Is there a specific header I’m missing?