If your Facebook page was connected to another messaging provider before Bookboost, linking the page is not enough. Facebook decides which app receives messages, and until that setting points at Bookboost, guest messages keep going to the tool you are leaving.
The setting is Facebook's handover protocol, and it lives on the Facebook page rather than in Bookboost.
When you need this
You are moving to Bookboost from another provider that also managed Messenger.
Your page is linked and activated in Bookboost, but Messenger conversations are not arriving.
If Bookboost is the first tool ever connected to the page, you can skip this.
Setting Bookboost as the receiver
You need an administrator account for the Facebook page.
Log in to Facebook as a page administrator and select the correct page from the profile menu.
Go to Settings & Privacy, then Settings.
In the sidebar, select Page setup.
In the central panel, select View under Advanced Messaging.
Under App Settings, select Configure next to Messenger Receiver.
Set Bookboost as the Primary Receiver, if it is not already.
Facebook's menus change. If the path above does not match what you see, search Facebook's own help for "handover protocol" or "advanced messaging" rather than assuming the setting has gone.
Confirming it worked
Message the page from a personal Facebook account and check that the conversation reaches the Unified Inbox. If it still lands in the old provider, the Primary Receiver has not changed.
What this does not do
It is not a Bookboost setting. The handover protocol belongs to Facebook, so we cannot see it or change it for you.
It does not disconnect the old provider. Removing their access is a separate job, and worth doing so nobody is answering guests from two places.
It does not bring your history across. Conversations handled by the previous provider stay with them.
It does not replace linking the page. Both are required. See Connect Facebook Messenger.
What to do next
If the page is not connected to Bookboost yet, do that first. See Connect Facebook Messenger.
Getting help
Open Help at the bottom of the left menu and choose Talk to Us, or email support@bookboost.io.