@MeTPForum Firstly the LED on the power adapter is green which means that powerline is already working. I think your main concern is that your internet speed is too slow but this could have related...

@MarcH Did you do the wired or wireless speedtest. If they were wireless speedtest, please have a check on the link speed. You can refer to the FAQ below:https://www.tp-link.com/en/support/faq/2265/...

Could you please try the beta firmware that we developed for your case? I have uploaded the firmware and local installation guide to the link below:...

@DdR From your description, we still can't have an intuitive impression of your network topology. If you can draw your network topology directly, it will be of great help for us to help you locate...