Wifi Connection Problem

I have a BT Router which broadcasts wifi. I also have a TP-Link Powerline adaptor to extend my wifi range. The problem is with the Powerline adaptor. It broadcasts a perfectly good wifi signal which is detected by wifi analyzer software. It uses 802.11n on 2.4Ghz band. However my laptop (Windows 11) says "Can't cannot to this network" when attempting the Powerline network but it is quite happy to connect to the BT network. If I attempt to connect to the Powerline network with my Android phone it comes up with Authentication Problem but the phone is quite happy to connect to the BT network. My old laptop, which I have now disposed of, would connect to the Powerline network so I know that the Powerline adaptor is working. Also, as I have explained, the Powerline network shows up on wifi analyzer software. I plugged the laptop into the Powerline adaptor with an ethernet cable to check that the correct signal was reaching the adaptor and that worked fine.

I have no idea what to do now to solve the connection problem with the new laptop and the phone as they both connect fine to the BT network but refuse to connect to the Powerline network although I know it is possible to connect to the Powerline network as my old laptop did so. I would be most grateful for suggestions.