Thinking about it logically, most using pfBlocker's DNSBL feature are probably using the actual DNS blocklists, so I bet the widget is looking for those items and they don't exist if only the SafeSearch feature is being used. Hence the error/warning.
To think out loud for the forum, we could use the feed and do something like either:
set Windows DNS to forward to pfSense set pfSense to forward to desired DNS (e.g. Quad9) set Deny Outbound rule to block using DoH feedor
set Windows DNS to forward to desired DNS create rule to allow Windows DNS to query desired DNS create rule to deny to DoH feed (using Alias Native, so one can set an order with a custom rule)Most of our clients use Windows AD; the smaller ones just query the pfSense directly, so we can just block DoH using the feed.
Edit: the Windows AD domain of course can be listed as a domain override pointing back to those servers on LAN.