Microsoft family sign in not sending authentication code

I was just having a similar problem. My son would try to login with his @outlook account and Windows demanded a code from the outlook email, but it never appeared. I went to a browser in my profile, logged in to his MS profile on the web, went to "Security" settings, and hit "Manage how I sign in." I saw that it was configured to send a code to my email. (I should note that I never got the codes in my email either) I removed that method from his profile, and Windows now prompted for the password rather than email code that never appeared.

You could setup codes to a phone as well I suppose. My son doesn't have one, so I didn't do that. 😉