What does "Let's keep your account secure" mean?
If you see a message like the one below that says, "Let’s keep your account secure" when signing in to your work or school account, it's because your organization or Microsoft needs another way to verify your identity during sign-in.
Why do I need to set up another way to verify it's me?
Another sign-in method helps increase the security on your account and helps prove who you are if you lose access to your account, or it needs to be recovered.
Note
Admins: In some cases, organization admins can remove the requirement to set up another way to sign in. Learn more about Providing a default level of security in Microsoft Entra ID.
If you see the message when signing in, choose one of these methods to add another way to sign in.
In the window that pops up when signing-in, select Next and follow the prompts to add another way to verify it's you.
On your computer, go to the Security info page of your MySign-ins dashboard. Select
Add sign-in method and follow the prompts to add another way to verify it's you.
See also
How to add your accounts to Microsoft Authenticator
Set up a mobile device as a two-step verification method
Common problems with verifying your identity
Signing in with a personal Microsoft account? See "Help us secure your account".