By any chance, do you use the Adblocker Ultimate add-on? There is some strange incompatibility with Firefox 116 that is affecting popular websites.
One of the reviews on the Add-ons site said: "Many sites stopped working after the 4 Aug update, but I managed to get them working again after going into the extension settings, Filters tab, and turning off the Security filter. The Ad filter continues to work fine."
You might want to try that temporarily until the conflict is resolved.
