Hello, thank you for reaching out to Microsoft Q&A.
You might receive this error if your account is temporarily blocked. Avoid making repeated attempts, as this will reset the time lock. So, after 24 hours,
Open an incognito tab on any web browser and use the following link to reset the password.
Make sure you switch your internet connection to Mobile data instead of Wi-Fi this time.
https://account.live.com/ResetPassword.aspx
See if you receive the verification code.
If you are still having trouble resetting the password for her account, you can use the account recovery form here to recover her account -
Remember to use a familiar device from which you've frequently accessed your Microsoft account, as well as a familiar location. Microsoft will review your responses and respond within 24 hours. If you are verified, instructions on how to log back into your account will be sent to you, and if you are not verified, you will need to submit the Account Recovery form again. You can do this up to 2 times every 24 hours.