Update concept-certificate-based-authentication-technical-deep-dive.md

Author: Justinha

articles/active-directory/authentication/concept-certificate-based-authentication-technical-deep-dive.md

@@ -75,7 +75,7 @@ Now we'll walk through each step:
 ## Single-factor certificate-based authentication
 
 Azure AD CBA supports second factors to meet MFA requirements with single-factor certificates. Users can use either passwordless sign-in or FIDO2 security keys as second factors when the first factor is single-factor CBA. Users need to register passwordless sign-in or FIDO2 in advance to signing in with Azure AD CBA.
-For PSI to work, users should disable legacy notification through mobile app.
+For passwordless sign-in to work, users should disable legacy notification through mobile app.
 
 1. Sign in to the Azure portal.
 1. Select **Azure Active Directory** > **Security** > **Multifactor authentication** > **Additional cloud-based multifactor authentication settings**.