I'm using a 2013 MacBook Air connected to the Internet via Ethernet using a j5 Create USB 3.0 adaptor. Every so often, I'll simply lose my connection -- sometimes for a second or two, sometimes for more than a minute. It always comes back, seemingly on its own. Sometimes I will try shifting the cord or connector a bit and get results, but I don't know whether that's legit or just a coincidence. What do you think might be the problem? My cable modem is rock solid, my Ethernet router seems to be running fine (but who knows). The Ethernet cable is just a couple of years old, and the connectors aren't damaged. My laptop seems to stay online when running Wi-Fi. Any troubleshooting thoughts?