Most incoming emails going to Junk Mail

I can't figure out why the vast majority of my incoming emails are suddenly being routed to junk mail. I am using Mail on iCloud.com on an up-to-date Windows machine. I saw only 2 new mail messages for a whole day yesterday and when I checked Junk I found what I expected, even emails from senders marked VIP were there.

Need some help on corrective action. Anyone?

P.S. When I try to move messages from Junk to Inbox, for some reason I get an error the message cannot be moved to Inbox at this time.