This issue can occur if the company was recently switched to Single Sign-On (SSO) authentication.
If a user did not sign out of CORE before the SSO configuration was enabled, the browser might continue using a previously cached session from the earlier login method. As a result, the user can be redirected to an unexpected page when attempting to log in using the standard CORE URL. This behavior occurs because the browser is attempting to reuse the previous authentication session instead of initiating the new SSO login process.
To resolve this issue, clear the browser’s cache and cookies so that a new authentication session can be created. You can also open CORE in an Incognito or Private browsing window and sign in again.