@geniusmusing It sounds like a firmware upgrade redirects IP address access to router.asus.com. I have always used IP addresses directly for any in-network access. Apparently, #Asus did not consider how this requirement plus #HSTS would interact.

My entire network is offline right now (other than some phone hotspotting during this extended move), but I now intend to do all my network config from a #RasPi that is only used for in-network management tasks.