I saw (apparently) the same problem documented in [https://support.mozilla.org/en-US/questions/1283107 |an old issue] an old issue, but the issue's marked closed at this point. I'm seeing new tabs fail to load, but if I take exactly the same URL and paste it into another tab, it loads instantly...thus, every other tab isn't loading. In reality, this isn't happening with every new tab, and it definitely goes in spurts, so when I start seeing this, it happens for most tabs; otherwise, I can go for hours with no problem. Typically, if I leave one of these hung tabs long enough, it will eventually (minutes later) load. This is happening on a newly-built PC with a weeks-old install of Firefox. Any idea what might be amiss? Pasting link directly below - the md syntax seems unhappy. https://support.mozilla.org/en-US/questions/1283107