While the library does offer textbook Reserves for some classes in print/physical form, we might also have your class's required reading in the general circulation that can leave the library or check out as an ebook. (Example: If you need to read any edition of The Scarlet Letter, we have many copies and editions!) However, if it is a e-textbook that does not license to libraries but only directly to students, we will not have access.
Try the following:
Contact your instructor for instructions on accessing your e-textbook or check their syllabus. There may be a course-specific code you need to access your materials or software you need to download.
See contact information for the Campus Bookstores, which may know about problems in publisher platforms.
Reach out to the publisher directly or Google your problem. There are often help pages online.