Learners Getting Stuck in Articulate Courses (in LearnUpon LMS)

I saw this problem when I administered Cornerstone, and it turned out to be nothing more than the quality of the internet connection and the LMS eventually timing out on the user; there was nothing that we could do and there was nothing that anyone on the Cornerstone side could do. I suspect this is the same way with all LMSes. Yes, we had the usual checklist to apply when the user experienced this problem, and that did solve the issue occasionally (turn off your pop-up blocker, disable other extensions, use a supported browser, etc), but fundamentally, there wasn't a solution.