When login uniqueness is enforced, each account is restricted to a single session at a time. When it is not enforced, each account can have multiple simultaneous sessions.
To enforce login uniqueness
Navigate to Portals > Portals.
To configure an existing portal, click the configure icon next to it. To create a new portal, click Add Portal.
Select Enforce login uniqueness.
Select the Enforcement method drop-down option to log out of the existing session automatically or to confirm Log out of an existing session.