Network flows *only* showing blocked

I've got a firewalla purple that Iv'e been using in router mode for several years.  For the past 3 weeks, my firewalla isn't logging any flows other than blocked.  The upload/download graphs are completely flatlined at zero, starting July 25, and no devices/users/groups show any activites or flows other than blocked for since that time.

Any hints/clues/ideas?