Country overseas and the trusted device list shows as unavailable. Same with my partners iPhone.
Seeing the same issue on iOS. Oddly, still works on macOS.
I suspect it’s just server overload. Too many people adding Security Keys. Once you enable Security Keys it has to propagate the new keys across all devices. You’ve also probably got a lot of people removing old devices right now and the server that populates this list is not used to the traffic since this is a pretty infrequently used feature.
E2EE also started rolling out globally today.
Give it 48 hours. Will probably resolve.