Settings Wants to use Windows.net to sign in

I’m accustomed to my office Outlook account sending me to the MS authenticator to enter a couple of digits to get into my mail. Suddenly, I’m getting this message that settings wants to use windows.net to sign me in and I can’t get past it. If I cancel, the message just sits there; if I continue, I get the usual two digits, but there’s nowhere to enter them on the next screen. It’s happening only in my iPhone. No problem with my iPad or Mac Mini. Screenshots attached.