I just had my house wired for ethernet jacks. In one bedroom, there are jacks on two walls. In the first box, there are two cables. One is the feed from the switch in the basement, and the other is the wire that feeds the jack on the other side of the room. If I connect the feed wire directly to a jack, that connection works fine. If I splice into the feed wire to supply the other jack, the farther jack works but the jack being fed directly stops working. I have triple checked the wiring with a cable tester. The wire coming from the switch in the basement tests fine. The wire that runs from the first wall box to the second jack tests fine. I'm not sure what is causing the issue, it makes no sense to me that the wires and connections pass with the tester but my laptop won't connect when I have both jacks wired. Any suggestions? Thanks in advance.