This method is a little more complicated to set up initially but can be more reliable than text messages if you’re frequently abroad, and is the more elegant solution.
Using the app, you’ll receive a pop-up notification on your phone when you or someone else tries to access your Office 365 account. You simply tap Allow or Deny on the notification to proceed, which is simpler than having to type in a six-digit code, especially if you access more than one Office 365 account.
Firstly, you should install the Microsoft Authenticator app from the app store on your phone, here on Google Play or here on the Apple App Store. You’ll need to approve permissions as they’re requested, such as permission to display notification and permission to access your contacts, if requested.
On your computer you’ll be presented with the Additional security verification screen.
Under Step 1: How should we contact you? select Mobile app.
Select Receive notifications for verification then click Set up.
In the Authenticator app on your phone, add an account and choose Work or school account.
Point your phone’s camera at the QR code on your computer screen, and when the app registers it, click Next on your computer.
The app will be verified, and you’ll receive a notification on your phone. Tap Approve.
Back on your computer, you’ll be asked to provide a phone number in case you lose access to the Authenticator app, which commonly occurs if you lose your phone or switch to a new phone.
Select United Kingdom (+44) as your country and enter your mobile number. As you’re using the full international number, you’ll need to remove the leading ‘0’ so 07837001001 becomes 7837001001.
Click Next then Finished.
You may see a window mentioning app passwords. You shouldn’t need app passwords, so click Finished.
Once set up, if you get an Authenticator notification on your phone when you’re not expecting it, make sure to tap Deny. Please contact My IT Guy as soon as possible as it could be a sign that someone is trying to gain access to your account.