unable to login ms defender app

Question

I would like to setup the pass key through authenticator app. Before that i am trying to login the MS Defender app. But unfortunately, it is not allowing to sign in. Looking for an help here.

Answer 1

To sign in to Microsoft Defender and set up a passkey via Microsoft Authenticator, first ensure that authentication is completing successfully in Authenticator and that any passkey issues are resolved.

1. Complete sign-in in Authenticator
   • If Defender shows something like “Authenticator did not complete login,” open:
     • Microsoft Authenticator, or
     • Company Portal, or
     • The primary Microsoft app on the device (such as Outlook/Office)
   • Finish the pending sign-in or approval there. If the authenticator (broker app) does not complete the process, Defender sign-in will fail.
   • If the password is forgotten or sign-in cannot be completed, contact the organization’s IT admin to reset or assist with the account.
2. Set up a passkey in Microsoft Authenticator (same device)
   • On iOS:
     1. Open Authenticator → tap Add Account (or +) → Work or school account → Sign in.
     2. Complete MFA as prompted.
     3. When prompted, select Open Settings → Passwords → Password Options.
     4. Turn on Autofill Passwords and Passkeys and under Use Passwords and Passkeys From, select Authenticator.
     5. Return to Authenticator and select Continue to complete registration.
   • On Android:
     1. Open Authenticator → Add Account (or +) → Work or school account → Sign in.
     2. Complete MFA.
     3. On the device, go to Settings → Passwords & Accounts → under Additional providers, enable Authenticator.
     4. Return to Authenticator and select Done.
3. Fix “passkey can no longer be used” or missing passkey
   • If a message appears that the passkey is not found, no longer valid, or can’t be used:
     1. In Authenticator on the mobile device, remove any passkeys that no longer apply.
     2. Set up a new passkey as above.
   • If a new device was recently obtained, set up a new passkey on the new device first, then remove old passkeys from the account.
4. Use Authenticator as the sign-in method
   • When signing in (for Defender or other Microsoft apps):
     1. Enter the username and select Next.
     2. Choose Send notification.
        • If needed, select Other ways to sign in → Approve a request on my Microsoft Authenticator app.
     3. When prompted to Check your Authenticator app, open Authenticator or tap the New sign-in request notification.
     4. Enter or tap the number shown and select Approve.

If sign-in still fails after completing Authenticator login and passkey setup, the tenant admin or IT support should review the account’s MFA and sign-in configuration and, if necessary, reset MFA methods.

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References:

• Authenticator Did Not Complete Login
• Troubleshoot signing in with a passkey
• Set up a passkey in Microsoft Authenticator
• Sign in using Microsoft Authenticator