The two devices must be connected to power outlets and electrical wiring which belong to the same electrical system.
Connect the adapter directly to the wall socket instead of a powerstrip/surge protector. Filtering circuits in the surge protector can interfere with power line technology.
By default all D-Link Powerline devices are configured to communicate with each other. Try factory resetting the adapters to establish communication if the above fails.
- Power on each adapter
- Press and hold the reset button (small pin hole) for 10 seconds and release.