Comment 2 for bug 1562733

As a sidenote, talkplugin is still needed for Firefox users (I don't know why, Firefox has fully functional WebRTC now, but there you go). Last published plugin package is of April 2015.

In the long term, it would make sense to modify upstream apt to clearly distinguish between the problems that are under the user's control and those under the repo owner's control, and report it e.g. via the return code or the error message prefix. Then GUI tools could give the user better advice than the misleading "Check your internet connection" message.