IMac says PDF created on iPad is corrupt, but I can open it on my iPad

I scanned the document to PDF using my HP printer/Scanner using the app on my iPad. My iPad can read it but when I try it in my iMac it says the file is corrupt. I tried a couple of different apps to Open it with the same result.

I then went back to my iPad, successfully opened the file and printed it to PDF. Again the iMac would not read this new file.