Hi @Sharon Naude ,
I understand that you can no longer use your previous device to preform the MFA prompts.
Work or School accounts registered with Microsoft Authenticator are device-bound. This means you will need to register your new device with your Entra ID work account before you can receive the number-matching verification or approval push notifications.
You can register new devices at https://aka.ms/security-info.
Before registering your new device you will need to get an administrator to reset your multi-factor using the "require re-register multifactor authentication" option in your user's authentication methods blade.
You can read about my experience of changing phones here: How I almost got locked out of 50+ accounts
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