i experienced the same thing, thatch why i moved back to 8, ssl problems, http, and other stuff that affecting the performance and usability to the customer
only firefox, yes disabling web protection and protocol filtering makes difference, i can browse it with either of them are disabled
no i dont have any other software that can intervene http, only eset
ESET 9 Blocking some sites including http sites, Firefox
use new firefox 42 and eset smart security 9
and browse this site hxxp://sourceforge.net/p/sevenzip/discussion/45797/thread/6cc0d82c/
it will show no content, just plain white page