Reputation Inbox users will no longer be able to respond to Google Business Messages that are older than 30 days.
Google now requires that all Business Messages be responded to within 30 days of the final incoming message. In the Reputation Inbox, Google Business Messages that have not been responded to within 30 days will be marked as Expired. Users can filter to Expired conversations in order to see Google messages for which responding is disabled.
As a reminder, Facebook messages do not accept responses after 7 days of the final incoming message.