The most likely cause is a defective cable or a connected device that is not running at 100 Mbps. Test the cable. This means the port is not ready. Unplug the power cord, then plug it in again to reboot the hub. If the port is still malfunctioning, try replacing the adapter card or cable on the attached device.
Tips Make sure the power cord is plugged into both the hub and the electrical outlet.
Make sure cable distances, repeater limits, and length between nodes do not exceed the IEEE 802.3u recommendations of 100 meters to devices like servers and workstations or 5 meters between hubs. Tighten all cable connections. Make sure all hubs are connected to the network. Make sure all network adapter cards and cable connections are in good working condition. Plug the other end of the cable into port 7X. 3.