I have searched the forum here and, as expected, many people have had this problem, but few actual solutions have been given other than those for complete newbies (download file; open in Reader...)
I could open this file in the past but now it's failing. I tried Reader DC (most current version) and when that didn't work I downloaded the trial version of Acrobat Pro but that just displays the same message. I looked at the PDF metadata and can see it was created in LiveCycle Designer 8.0.
File Permissions : rwxrwxrwx File Type : PDF File Type Extension : pdf MIME Type : application/pdf PDF Version : 1.7 Linearized : No Tagged PDF : Yes