When I open Kindle Cloud Reader on Firefox (v58), it takes very long time (practically forever) to load my library. Other buttons on the site seem working and I can go to kindle store or access my notes and highlight, but only a spinning a wheel is shown in the library. This seems to happen on Firefox only, Chrome and Vivaldi works. I tried disabling tracking protection and privacy protection add-ons, but it didnot work. The guidance here https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can also didn't work. How can I solve this?