You can sign in from any device — a desktop at work, a laptop at home, a tablet on the move — but your account runs one live session at a time. Log in somewhere new while a session is already open, and the earlier one is signed out; the newest sign-in becomes the only active session, and the device it displaced is told that someone has signed in to the account.
This is not a restriction on which devices you own or a cap on how many you may register. Every device is welcome; what the account holds to is a single sign-in being live at once. Switching machines simply means the latest login takes over and the previous one steps aside — no setting to change, no device to pre-approve.
How EduSum Keeps One Live IT Exam Session
Handing the live session to the newest sign-in is an account-integrity feature, and it reads cleanly against a security exam topic: a stale or stolen session is dangerous mainly for how long it stays valid. If a session token were left alive on a borrowed or public machine, anyone returning to that screen could pick up where you left off. Because a fresh sign-in retires the previous session, a stale one cannot stay open in parallel — the moment you sign in again, any earlier session on another device is closed out. One live session is easier to reason about, and safer, than several running unseen.