Can't re-establish powerline ethernet link

Connected one end of a Linkpro Powerline 200M Ethernet bridge to a router and a wall socket and the other end to another wall socket in the same room and a laptop computer. Checked it was working, set the secure network key up and then moved the laptop to a room at the bottom of my garden. The connection worked very well until the laptop battery ran out.

Plugged in the laptop power supply but couldn't re-establish the connection.

Have tried repeating the whole exercise, including doing factory reset of both the ethernet bridge adapters. Can only get ''little or no network connectivity'' in the garden room now.

I'm assuming I don't need a phase coupler on the grounds that I got good connectivity the first time I tried it.