Microsoft will be making a change to Microsoft's Authenticator app on May 8. 2023. A new process called “number matching” will be enforced ON by default.
Now instead of just hitting approve on the Microsoft Authenticator app on your phone, you will be prompted to enter in a number as shown below.
On the device you are attempting to login from, a prompt will come up to “Approve sign in request”. You will then need to open your Microsoft Authenticator app on your device and enter the number shown to sign in.
Enter the number in the “Enter number here” box provided on your device. Choose “YES”.
After entering the number in the Microsoft Authenticator app, you should see a successful login into the webpage or service you are attempting to use.