If you've connected a Facebook Messenger account to a conversations inbox, but incoming messages aren't appearing in the inbox, you may have another app set as the primary receiver in your Facebook settings. When two different chatbot apps are integrated with a Facebook page, the primary receiver app controls and receives all incoming messages by default. To set HubSpot Conversations as the primary receiver:
Log in to your Facebook Business Page.
In the left sidebar, navigate to Settings > Advanced Messaging.
In the Handover Protocol section, next to Messenger receiver, click Configure.
Click the Primary Receiver for Handover Protocol dropdown menu and select HubSpot Conversations.
With HubSpot Conversations selected as the primary receiver, incoming messages should now appear in your conversations inbox.