I have a user that is in an Azure domain and trying to use their Azure creds to sign in at http://login.microsoftonline.com/
It seems to get stuck at "Enter Code". "Please type in the code displayed on your authenticator app from your device".
In Azure I have activated MFA, reset the users MFA, proved it works with and without MFA at portal.office365.com but when sign into http://login.microsoftonline.com it asks for an extra MFA that I don't have... The microsoft account is definitely from Azure as I do a password reset and the new password works at http://login.microsoftonline.com.