Session &1, which has no user, is not authorized for the element &2. (Surrogate &3).
&1 - Session ID
&2 - Name of the site element
&3 - Surrogate (unique identifier) for the site element
A session, where no user has yet logged in, tried to access the specified
site element without being authorized to it.
A generic error message has been shown to the user.
As the session is not authorized for the site element, the site element should
not have been possible to access for the user.
However, it would be possible for this situation to occur if a menu item has
been loaded and shown to the user - after which the authorization has been
changed. When the user later tries to access the menu item this error will
occur.
Check whether the authorization of the site element has been changed.
If not, you should investigate how the user has been able to activate the
menu item.