Same problem since Firefox update.
Tried all the same potential resolutions as above. No change. It has additional problems of rendering you unable to message your CC friends, unless you switch to another browser which works correctly.
Firefox has the best and smoothest swing meter, for me, which is why I use it.
On top of which today I had an error # 1075 as I tried to start a Strokeplay tourney. Pressed the tee off button and was greeted with an Ineligible to play tournament message.