If you had Microsoft Authenticator set up on an old phone and you got a new phone with the same phone number, you'll need to get it set up on the new phone.
(While many of your apps may transfer their settings when you restore your new phone from the backup of your old phone, Microsoft Authenticator will not do this, and will need to be reconfigured for your account on each new device.)
***If you got a new phone number, let IT know and we will work with you to get your MFA settings deleted so that you can start the process from scratch***
First step is to make sure the Microsoft Authenticator app is installed on the new phone.
Next, on a web browser on your computer, navigate to mfa.interpublic.com and sign in if prompted. Choose Microsoft MFA Registration, and click the big blue button that says Microsoft MFA Registration on the following screen.
At this point, you may receive a prompt to Approve sign in request, or to enter a code from the Authenticator app, neither of which you'll be able to do because that app was set up on your old phone.
Click "Sign in another way" and, on the screen that appears, choose "Text +X XXXXXXXXXXX". Then, enter the 6 digit code that is texted to you at the following screen.
Next, click Devices and Preferences, which will take you to a screen which should show a bunch of information which you set up when you initially set up MFA Authentication. Click "Set up Authenticator app", and this will take you to a screen with a QR code. Open the Authenticator app on your mobile device, and choose to add a work or school account (and allow the app to have access to your camera if it asks). You should then be prompted with a camera square which you will use to take a picture of the QR code which should be on your computer screen. Once successfully scanned, click the "Next" button on the lower right hand corner of the QR code popup on your computer. You may be sent a request to approve, which you should do, and follow any prompts to finish up the set up.