On the "desLibris in your Library" panel is an "Access Denied" link, which will present a list of all titles where users have attempted to open a book but have been denied access.
There are three reasons why access may be denied.
The most common is that the title is not in your library's entitlement.
If the book is in your entitlement but is licensed for Single-user access, access may be denied if the book is being used by another patron.*
Access may also be denied where a concurrent user limit is in place.
*For this reason, download is automatcally disabled for Single-user licenses.
Using the Checklist view, you may either add the selection to your cart or your Acquisition Profile for further purchase consideration.