The platform says you need to have Adobe Digital Editions installed, and I have got that, but it doesn't work. I also tried on Ebsco ebooks but it was the same thing.
Most likely the format of the file you have tried for downloading is PDF. If an alternative is offered such as epub, try that.
If there's no alternative to PDF, follow one of the solutions below to associate the .acsm format with Adobe Digital Editions instead of Acrobat.
(The .acsm file is the authorisation key that should allow your specific ebook to open in Adobe Digital Editions.).
Windows users might also like to try using Bluefire Reader for Windows.