Debugging AutomaticUpdater

I have a Windows Forms .net 4.5.2 application, to which I have added the AutomaticUpdater control, largely following the procedure here: http://wyday.com/wybuild/help/automatic-updates/automatic-updater-for-your-.net-app.php

On my test machines, everything is (mostly) working fine. I build a new version in wyBuild, the AutomaticUpdater "notices" it and gives the option to install it, so far so good.

However, when I give an alpha copy to the client to test, it seems very hit and miss whether the automatic updater "notices" the update. Again, this appears to work 100% on my test machines, no variation at all, but from them I get complaints boiling down to "it says no updates are available" (when they are), and "it looks like it updated, but I don't see the new version" (they are not at all technical, unfortunately).

So my question really is how and where do I best add debugging/logging information to work out what is going on? I'm afraid I only have a fairly basic understanding of the update process, though I *have* read the documentation fairly thoroughly.

Many thanks,Aaron