My Adobe Digital Editions DRM PDF eBook reads fine BUT why can't I read in Acrobat using the same Adobe ID?

I bought an eBook, came as ascm.file, viewed as DRM PDF in Adobe Digital Editions. I can view the eBook fine in ADE but it's useless as far as efficiently & effectively reading & note-taking using the PDF. Thus, I want to open the PDF in Acrobat which is a million times better. My Adobe ID used for ADE is the same I use for Adobe Acrobat Pro DC (which I pay for). Why can't I view the PDF in Acrobat? I receive an error message stating "There was an error opening this document. The security plug-in required by this command is unavailable."