Welcome to Android Central! Do you mean that the switch won't turn on at all, or it turns on, then turns off after a few seconds? Or that the wi-fi radio turns on, but won't connect to a network?
I have exactly the same problem. I can slide the tab over, it reads "tuning on", then goes back to the left, and nothing. I have hard reset my Tab s 10 3 times, no luck
Welcome to Android Central! It could be a firmware or hardware issue. You could try reinstalling the firmware using Smart Switch. If that doesn't help, then you may have to bring it to a repair shop. It might something as simple as a loose connection.