Faulty equipment

[Waxy1]

The cable, or the openreach port, is faulty. I have to push the cable in further into the SDX611 openreach port to make a stable LAN connection. 
just like when you have an old phone charger and you have to hold it at an angle it in the right way for your phone to charge. I have to do the same thing with the LAN cable to provide any stable internet access

[Chrisee]

@Waxy1 if your ONT has a faulty Ethernet socket contact Sky so they can getvOpenreach to replace the unit. However with Ethernet it is often a fault in the plug which has a retaining clip to hold it is place.  If the clip on the connector is broken the normal thing to try first is to replace the cable which can be bought at pretty much any hardware shop and most supermarkets. You do not need anything special.