WatchGuard issues

Safari was running slowly so I googled how to make it faster. One website suggested deleting all my safari extensions and plug-ins, so I did so. Then I tried going onto Instagram and a pop-up page showed up saying: "Request denied by WatchGuard HTTP Proxy.". I have no idea what this means, I have googled how to block WatchGuard but I don't even know if I want to do that. I just want to be able to go on Instagram again.