Already do this. Even more - Hold 8-15 sec and reset both devices. And than sync them - same issue.You could try to re-link both of the devices.
Hold 5 – 8 seconds. A new security key is generated. This is needed to remove a PWR-LINE PRO device from an existing PWR network.
after that, re-link -
Hold 0.5 – 3 seconds. For 120 seconds will try to communicate with another PWR-LINE PRO device.
i will try this later today. but if the problem in wire why LED "Sync" are ON?Those devices have no software (no OS), so this is the reason why you can't connect to them and there is no "utility".
Did you try to connect them to other outlets, to put them closer to each other?
Thru couple of 16A automatic switches and DIN attached outlets. Cable length ~50m.Are they plugged directly into the wall (not via power bars etc)??