Internet Radio not working on Apple TV 3rd generation

A while ago Internet Radio was working just fine on my ATV3.

Today I get the error "Cannot access Internet Radio stations."

"Check your network configuration and try again."

Restarting does not help.

All other network-related functions (e.g. streaming movies, music, podcasts) work just fine, so there cannot be any network issues. There have been no changes made to the WiFi network.

So has Apple quietly dropped Internet Radio functionality from ATV3?