個人アカウントでAzureに複数のサブスクリプションがありますがAuthenticatorが開かずサインインできなくなりました

Hello @Shigeki Shoji ,

Greetings of the day !

Based on what you described, it sounds like the authentication method has changed from Microsoft Authenticator Push Notification (Number Matching) to Authenticator One-Time Passcode (OTP).

Previously, Azure sign-in displayed a 2-digit number and your iPhone received a push notification from Microsoft Authenticator. You entered the displayed number in the app and approved the sign-in. This feature is called Number Matching.

Instead of receiving a push notification, Azure is asking for a verification code. The Authenticator app shows an 8-digit code, while the sign-in page only accepts 6 digits.

A common cause is that the Authenticator app is registered with the wrong account type (for example, a Personal Microsoft Account instead of the Azure/Entra account being used for the subscription), or the MFA registration became corrupted/out of sync.

1. Verify which account is in Authenticator

Open Microsoft Authenticator and see whether the account is listed as:

• Personal Microsoft account
• Work or School account

If Azure is asking for MFA on an Azure tenant, it normally expects the Work or School account registration, not the Personal Microsoft Account registration.

2. Look for an approval request

If no push notification appears:

• Open Microsoft Authenticator manually.
• Pull down to refresh.
• Check whether there is a pending sign-in request waiting for approval. Microsoft documentation notes that in some situations the notification may not appear, but the approval request can still be available inside the Authenticator app.

3. Re-register Microsoft Authenticator

If the account only shows an 8-digit code and Azure expects a 6-digit code, the MFA registration may need to be reset and configured again. Do register the MFA for this user account with an any other global admin in that tenant

4. If you are the only administrator

If this is a personal Azure tenant and you are completely locked out, Microsoft treats it as a tenant lockout scenario. We have to engage our Microsoft Support/Data Protection had to assist with MFA recovery.

Based on what you described, it sounds like the authentication method has changed from Microsoft Authenticator Push Notification (Number Matching) to Authenticator One-Time Passcode (OTP).

Looking forward for your response. Let us know if you have any queries. Happy to assist you further.