If you are able to access the course, and you are able to access other digital resources but not the e-book within the course, it is likely that you have used an access code that came bundled with a third-party e-book (e.g., VitalSource, Kortext, etc.). Since you already have access to the e-book through that third-party platform, the access code you received does not provide you with access to the e-book from Oxford Learning Link.
If you think there is a different problem occurring, please Contact Us with your name, institutional email address, and the course title, and we will investigate.