@Clive_A - new device, and never imported a backup. I haven't removed and re-added the WANs, due to the scary messages about losing the entire configuration if I do, and I was worried about restoring...

@Clive_A - unfortunately not. I've rebooted any number of times. Tried an incognito browser (Chrome) and also tried in Edge (which had never previously been anywhere near the site). Other hints?...

I have three ISPs (cable, DSL, cell), each run into one of WAN, WAN/LAN1, WAN/LAN2. All connections seem to be working, and to a degree traffic is flowing. (Just rebooted, so traffic is low.)...