Custom URL and Instance URL AuthenticationSummaryWhen accessing the instance using a Custom URL, the user will be challenged for authentication. If a new browser tab is opened, and the Instance URL is entered, the user will again be challenged for credentials again. (The same will happen if the instance URL is used first, then the Custom URL.) This will result in 2 different sessions being created in the instance. It is not possible to "combine" these 2 URLs into one session. Sessions are based on URL, and the sessions will not be shared between URLs.