? ebook will not download

I am correctly registered, have successfully authorized my 2015 MacBook Pro, have latest ADE version as well as Adobe Reader XI (both of which my online library requires); I seemingly can download an .acsm file, but although when I try to open it I get a prompt saying "Fulfilling [title of book] / Downloading Content," the prompt window has gray "ADE" and "Cancel" tabs and the download progress bar is just gray. Following an Adobe suggestion somewhere, I found the download files and double-clicked on those, but nothing happened. Can anyone help?