Can i use two authenticator app for a single account in different device?

Yes, you can use two authenticator apps for a single account on different devices. Refer to How to add your accounts to Microsoft Authenticator - Microsoft Support.

To do this, you'll need to set up the authenticator app on each device separately. Here’s a general process you can follow:

1. Download and install the Microsoft authenticator app on both devices.

2. On the first device, add your account to the authenticator app by scanning the QR code provided.

3. On the second device, repeat the process by scanning the same QR code or entering the same setup key.

Or you can add the authenticator app by clicking/ going to My Sign-Ins | Security Info | Microsoft.com and choose Add sign in Method. See the screenshot below, you can see that I'm using two authenticator app with different phones.

This way, both devices will generate the same time-based one-time passwords (TOTPs) for your account.

If you need detailed steps for a specific authenticator app, feel free to ask!

The authentication application installed last would delete all entries on the MS Authenticator backup server during its first synchronization, and the authentication application installed first would then delete all its local entries during its next synchronization. As there is no longer a backup, all affected logins can no longer be accessed as the corresponding data is missing. However, with the second installation, the user wanted an additional authentication application as a backup in case the authentication application usually used is not available.