Can't log in to Outlook.com as i lost my device where authenticator installed

To regain access after losing the device with Microsoft Authenticator, follow the path that matches the current situation.

1. If at least one security method (phone/email/Auth app on another device) is still accessible

• Go to the Microsoft account sign-in page and start signing in.
• When prompted for verification, choose another available method (SMS, email, or another registered app/device).
• After signing in, immediately update security info:
  1. Open the Advanced security options page of the Microsoft account. Sign in
  2. Select Add a new way to sign in or verify, then add a new phone number, email, or Authenticator on the new device.
  3. A security code will be sent to the new method; enter it and select Next.
  4. Expand the old/lost method (old phone/Auth app) and select Remove, then confirm.
• Do not remove all existing security info at once; otherwise the account may be restricted for 30 days.

2. If the password is known but there is no access to any security info (lost phone and no usable SMS/email)

• Begin sign-in to the Microsoft account. Sign in
• At the Verify your identity prompt, select I don't have any of these.
• Follow the instructions to replace security info.
• After replacement, there is a mandatory 30‑day wait before normal sign-in is allowed. During this period, if the old security info becomes available again, it can still be used to sign in, but doing so cancels the pending update.

3. If the password is forgotten and there is no access to security info

• First try to regain access to any missing security info (phone/email) if possible.
• If that is not possible:
  1. Review the guidance in Help with the Microsoft account recovery form.
  2. Submit a request using the account recovery form to prove ownership and recover the account.

4. If Outlook.com says the account or username is not recognized

• Use the guidance under I can't sign in to my Microsoft account:
  • If the username is not recognized, see My username has stopped working.
  • If the error says "We couldn't find an account with that username" or "account doesn't exist", use the Sign-in Helper tool.

5. If the device was lost or stolen and this is a work/school account

• Sign in using a different method if any are available.
• Contact the organization’s Help desk and ask them to clear the MFA settings for the account. After they clear the settings, the account will be prompted to register MFA again at next sign-in.

These are the supported self-service and support paths to regain access and update security methods after losing the Authenticator device.

References:

• Troubleshoot Microsoft verification code issues
• I can't sign in to my Microsoft account
• Common problems with two-step verification for a work or school account
• Restore account credentials from Microsoft Authenticator
• How Do I Regain Access to My Account After Losing Access to Microsoft Authenticator? (Urgent Request). - Microsoft Q&A
• I have a Micrsoft business account and I am the admin and the only user registered under this account. I can't log in because i have replaced my phone and the authenticator doesn't work. - Microsoft Q&A
• My personal hotmail account hacked by hacker with authentication app enabled. - Microsoft Q&A
• Can't sign in to my email - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A