The fly lead is the cable that connects the network card in your computer to a network point (usually on the wall). A non-operational network fly lead could also cause failure in the internet connection. The network fly lead is seated in the network slot on your computer.
This slot is located either at the back of the computer or on the side, depending on your PC/laptop. Ensure that the fly lead is plugged securely into the network point on the wall.
Check whether the cable or point has been damaged. If so, seek assistance from a network administrator.
Your fly lead could be faulty or damaged. To check if your fly lead is faulty, borrow a working fly lead from someone and repeat the previous steps with the borrowed fly lead.
If this borrowed fly lead works, your own fly lead is faulty. Seek assistance from a network administrator.