Unable installing extensions from a different feed

I added a new feed from a path, and WAC is telling me it can't read the feed or update the corresponding catalog.

I followed the instructions in this link: "https://learn.microsoft.com/en-us/windows-server/manage/windows-admin-center/configure/using-extensions#installing-extensions-from-a-different-feed".

In fact, since my network isn't connected to the internet, I also followed the instructions in this other link: "https://learn.microsoft.com/en-us/windows-server/manage/windows-admin-center/configure/using-extensions#installing-extensions-on-a-computer-without-internet-connectivity".

Regarding adding a file share as a source, it must meet the criteria outlined in this link: "https://learn.microsoft.com/en-us/windows-server/manage/windows-admin-center/configure/using-extensions#installing-extensions-from-a-different-feed".

However, I'm getting these error messages and therefore don't have any extensions available to add: