Hi Grinchlady,
From the above message, if we understand correctly you have been receiving the error message on MAC computer while accessing the pdf file in Adobe Reader DC application?
Could you please share the exact error message that you get? Is it something related to the "com.apple.webkit.plugin.64 want to use your confidential information"?
If it is same, then check the troubleshooting steps suggested in- "com.apple.webkit.plugin.64 want to use your confidential information"
Please share the exact information to help you in better manner.
Regards,
Akanchha