So I've been having this problem for a couple months, and it happens both with Safari and Firefox. Occasionally, a specific website will stop loading. It happens with websites I use a lot, like Facebook, Google and the New York Times. At a random time, when I type in the URL, it will say "page cannot be opened". Other times, a website will start randomly redirecting to a different page, so when I type in NYtimes it will go to some blog, and sometimes it will say "warning this appears to be a website pretending to be facebook (or google)".
The only way I can fix this is by resetting Safari, emptying the cache, and restarting the computer. Sometimes just restarting won't work, and I'll have to shut down the computer, leave it for a bit, and then start again. I've tried switching to Firefox but the same thing happens there too.
Does anyone have any idea why this could be happening?