Hello, good day and thanks for your question. To add to the above, please check out the additional information for this.
Check Recent Sign-in Activity
- Open https://account.microsoft.com/security from a browser.
- Click Review recent activity and from there you will see if the activity that happened on your account.
- If you seen anything suspicious, click Secure your account from that page and go through from there.
Check Your Authenticator App
(Microsoft Authenticator cannot easily be compromised or be broken into)
- Check if your phone itself was compromised (this happens when it is rooted or unlocked).
- There is also a possibility that you might have approved a fake login prompt (via phishing).
(To check the Microsoft Authenticator)
- Open the app.
- Go to settings > Account backup.
- Check if backup is enabled (and which account it’s tied up to and this should be your account if this is enabled).
- You may also check if Device registration is enabled under the account name and this will show that it is linked to your device.
Review and Change Saved Passwords
Change Passwords Immediately
- Change your Microsoft account password.
- Any email accounts that you are using for recovery.
- Any critical services that you are using for banking, password managers, work, etc.
- It is important to use a new, unique password, hard to guess and update your 2FA settings as needed.
Revoke Trusted Devices & App Sessions
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.