My machines are not connecting to my backoffice

[Admin]

If you have a "Hub" or "Switch" that connects the cables to your PC, ensure that it is switched on. If it has power, but all the lights stay on - not blinking, switch it off for 30 seconds & then on again.

If you know how, browse your network to see if you can detect other pc's on the network.

If you can't, ensure that you have not disabled your network card!