Suddenly. Within the last couple of days.
Please provide more information on this, like a feed URL that isn’t working.
Three are:
feed://news.google.com/?output=rss
dewaynenet.wordpress.com/feed/
feed://tidbits.com/feeds/tidbits_blurb.rss
Does it work again after rebooting the computer?
That did it, after a while.
(I always think of a reboot as a Windows hack.)