i had The same issue but it not was a change in a switch. I have 3 sp20 and one of them suddenly fail and couldn't find it in my network. no led light just fan and Ethernet lights worked. I tried to restore the miner several times and finally works. then, the miner worked fine for a day and had the same failure again. I had to call spoondoolies tech support and return back the miner . I believe that was problem in the controller board works some times and fail again. try to connect the miner again directly to the router . I hope it works