Suppliers confirm their email with a one-time code before an assessment opens, so an assessment and its data stay with the people it was sent to.
The emailed link carries their address, so the sign-in screen prefills the email and they enter the code sent to it. All four assessment emails — invite, reminder, bulk and result — carry the prefilled address, and the code email is branded with your name rather than a generic sender.
Suppliers who arrive from the supplier portal, already signed in, skip the code. When a signed-in email is not on the assessment's authorised list, they see a clear no-access screen with a prompt to sign in with the address it was sent to.
Suppliers who sign in this way do not get a Brand Cloud user account created. Admins can open any assessment with their existing access.
If a supplier reports they cannot get in, check they are using the exact email the assessment was sent to — the recipient must be able to receive the code at that address.