Just wanted to share a snippet of information that I discovered (and posted to the adobe enterprise forums) a couple months back (https://forums.adobe.com/thread/2191576):
Something that I discovered here is that you need to add a wildcard MIME type on the ACC/services/fcc folder (more specifically the validation folder) because the validation files don't have an extension so it was throwing back a 404.Hopefully this fixes it for you!
Just a little more clarification, the setup documentation from Adobe for the Adobe update server doesn't (or didn't) include this step when you were adding in MIME types for .dmg and .sig, so the server was throwing mime type errors and not returning the files to the client.
Feel free to pass this along to anyone who may have these issues!
