I have been an avid user of the Firefox browser on my PC for over a decade but a few days ago, when I tried to access a website on my Firefox browser, it would not connect me to the website. I have many tabs open in my browser and when I try to access any of the tabs, I get the same problem. There's a dot that moves endlessly back and forward in the tab while the screen remains blank. In the heading next to the website address it says "not secure", but it is saying this for all the websites that I was previously able to access and any new website that I enter. How can I fix this to access websites? I have tried restarting my computer but that has not fixed it.