A new screen after entering user name and password

A friend uses her Hotmail account daily but 2 days ago found that after entering her user name and password another screen comes up saying a password is not enough and asking for her phone number or another email address. This is blocking her access to he emails.  This is not happening on my hotmail account nor the accounts of anyone else it has been mentioned to.  She is understandably reluctant to enter her phone number and doesn't have another email account.  Can anyone confirm if this is genuine.  Many thanks