Using QWebEngineView (Qt 5.8 Windows 10, QtCreator 4.2.2, the same problem also appears in Fedora 26) to access an HTTPS site, I always get an empty document once the download has been completed. Searching the internet, it appears this is a fairly common problem, but I have yet to find a solution to the problem.
I assume I need to do something regarding SSL and/or javascript (the site I need to connect to, specifically uses javascript to do everything) but I haven't figured out how to do it yet.
SSL is working fine in other part of the program, both on Windows and in Fedora. Looking at the source of the downloaded document, reveals that nothing is contained in the page; connecting to the load* signals, there is evidence that some elements are being downloaded and redirects are followed.