I was previously using ADE 4.5.10 to view particular documents from a vendor that were subscription based.
With no change to my system, when I went to open the documents in my library, the following error appeared.
The vendor files are activated by acsm files. It does not occur on any other documents I have in my library, with the only notable difference is that the other documents I have are ebooks versus acsm files. I have contacted the vendor, and they have indicated there is no issue from their end.
I have performed the following troubleshooting actions:
checked PC time is automatic
deauthorised/reauthorised my account
uninstalled/reinstalled ADE on my PC
removed ADE from all other devices
uninstalled, and removed ADE files from PC registry, reinstalled