Update powerapps_mobile_troubleshoot.md

Author: mduelae

powerapps-docs/user/powerapps_mobile_troubleshoot.md

@@ -23,7 +23,21 @@ This troubleshooting article helps fix common issues for the [Power Apps mobile
 
 ## Sign in issues
 
-**Common errors**
+### Unable to sign in due to Microsoft Authenticator app
+
+If you don’t have Microsoft Authenticator app, download the app from the App Store or Play store and then sign in to Power Apps mobile again.
+
+If you already have Microsoft Authenticator app installed and you're are having issues signing in, then try this:
+
+1. Back up your Microsoft Authenticator account. For more information, see [Back up and recover account credentials using the Microsoft Authenticator app](https://docs.microsoft.com/azure/active-directory/user-help/user-help-auth-app-backup-recovery)
+2. Uninstall Microsoft Authenticator app.
+3. Uninstall the Power Apps mobile app.
+4. Reinstall Microsoft Authenticator app and add your back up accounts.
+5. Reinstall the [Power Apps mobile](https://docs.microsoft.com/powerapps/mobile/run-powerapps-on-mobile#install-power-apps-mobile-app).
+6. Open Power Apps mobile and then sign in.
+
+
+### Other sign in errors 
 
 - **Your device configuration is preventing sign-in**
 - **There was a problem signing you in**