COAR works on my phone (don't use that much cause I have a very limited data plan). COAR works on my lady's computer (Windows). COAR even works on her account on my computer (Mac). COAR does NOT work on my main account on my computer, making it hard to do things like log on to COAR and stuff.
It's an older-ish MacBook, running what should be the latest version of Safari, and it worked just fine until the other day.
How does this happen, how do I fix it, and how do I avoid it happening again?