Unable to open some PDF files with latest version of reader;can't click on links
Today, i was trying to open some pdf files from the website FlightAware.com, that I save for accessing past flight information (as opposed to saving the web page directly in my browser; it updates each day if I do that). I used Firefox for a dozen of these files, and when I try to open some files saved from late 2018 and early 2019, one of these two things occur:
1. I am able to open the file, but I can't click on any hyperlinks (shown in blue) within the file. When I move my cursor over the blue text representing the link to info about a specific flight on a specific date, the dog-bone icon displays instead of the pointing hand icon.
2. When I try to open a file from December 2018 or January 3, 2019, I get this error message (shown in screenshot below)

As far as I know, I have been able to open these files in the past without any problems. Any suggestions would be appreciated. I would like to know what solutions you guys may have short of just deleting these files (which I don't want to do, because I need them).
Thanks,
Evan
