How to fix a Safari problem with “v4.services.acrobat.com”

Macworld reader Jim keeps seeing an annoying message every time he opens a website in Safari: “com.apple.WebKit.Plugin.64 wants to use your confidential information stored in ‘v4.services.acrobat.com’ in your keychain,” along with a prompt to enter his password. IDGAn outdate plug-in produces this message repeatedly in Safari in High Sierra.This was a bug in Adobe Acrobat DC and Reader DC, which was fixed in a November 2017 update. (“4226351: Multiple safari keycha