Does a laptop connected directly to the Ethernet connection in your shop work? If not, it's that cable. You can buy an inexpensive ethernet cable tester and verify. Otherwise you are saying that you have set up the access point in the house, and with it connected to your network, everything runs great. But when you simply move it to the cable that runs to your shop, it fails to work? disconnect the shop ethernet cable for the switch in your house and connect a shorter cable between it and the access point. If it doesn't work, the port on your switch is bad.