@Misha123456789 

Hi, the middle LED is powerline LED, powerline LED off means the two powerline adapters are not paired with each other, thus internet will not work when you connect to the second powerline adapter.

In order to pair them again, please make sure they are in the same electrical circuit or move them into one room first, plug them both into wall sockets instead of extension board, then pair them via pair button:

1. Press the pair button on one unit for 1s, make sure power LED starts flashing

2. Press the pair button on the second unit for 1s, make sure power LED starts flashing as well

3. Wait for a moment to see if powerline LED will light up on both units

4. After pair successfully, please relocate them, connect one unit to your router via Ethernet cable, connect another unit to your client device, check the powerline LED again and test internet access.